diff --git a/meshroom/ui/qml/GraphEditor/CompatibilityManager.qml b/meshroom/ui/qml/GraphEditor/CompatibilityManager.qml
index d9cad1eed9..d2ea318dbf 100644
--- a/meshroom/ui/qml/GraphEditor/CompatibilityManager.qml
+++ b/meshroom/ui/qml/GraphEditor/CompatibilityManager.qml
@@ -14,7 +14,7 @@ MessageDialog {
     // the UIGraph instance
     property var uigraph
     // alias to underlying compatibilityNodes model
-    readonly property var nodesModel: uigraph.graph.compatibilityNodes
+    readonly property var nodesModel: uigraph ? uigraph.graph.compatibilityNodes : undefined
     // the total number of compatibility issues
     readonly property int issueCount: (nodesModel != undefined) ? nodesModel.count : 0
     // the number of CompatibilityNodes that can be upgraded
@@ -47,7 +47,10 @@ MessageDialog {
 
     title: "Compatibility issues detected"
     text: "This project contains " + issueCount + " node(s) incompatible with the current version of Meshroom."
-    detailedText: "Project was created with Meshroom " + uigraph.graph.fileReleaseVersion + "."
+    detailedText: {
+        let releaseVersion = uigraph ? uigraph.graph.fileReleaseVersion : "0.0"
+        return "Project was created with Meshroom " + releaseVersion + "."
+    }
 
     helperText: upgradableCount ?
                 upgradableCount + " node(s) can be upgraded but this might invalidate already computed data.\n"
diff --git a/meshroom/ui/qml/GraphEditor/GraphEditor.qml b/meshroom/ui/qml/GraphEditor/GraphEditor.qml
index 3262c62258..ab352a93c0 100755
--- a/meshroom/ui/qml/GraphEditor/GraphEditor.qml
+++ b/meshroom/ui/qml/GraphEditor/GraphEditor.qml
@@ -441,7 +441,7 @@ Item {
                 MenuItem {
                     text: "Submit"
                     enabled: nodeMenu.canComputeNode && nodeMenu.canSubmitOrCompute > 1
-                    visible: uigraph.canSubmit
+                    visible: uigraph ? uigraph.canSubmit : false
                     height: visible ? implicitHeight : 0
                     onTriggered: submitRequest(nodeMenu.currentNode)
                 }
@@ -759,7 +759,7 @@ Item {
                             flat: true
                             model: ['Minimum', 'Maximum']
                             implicitWidth: 80
-                            currentIndex: uigraph.layout.depthMode
+                            currentIndex: uigraph ? uigraph.layout.depthMode : -1
                             onActivated: {
                                 uigraph.layout.depthMode = currentIndex
                             }
diff --git a/meshroom/ui/qml/GraphEditor/NodeDocumentation.qml b/meshroom/ui/qml/GraphEditor/NodeDocumentation.qml
index 337f3e3711..3c63d2eff5 100644
--- a/meshroom/ui/qml/GraphEditor/NodeDocumentation.qml
+++ b/meshroom/ui/qml/GraphEditor/NodeDocumentation.qml
@@ -31,7 +31,7 @@ FocusScope {
             selectByMouse: true
             selectionColor: activePalette.highlight
             color: activePalette.text
-            text: node.documentation
+            text: node ? node.documentation : ""
             wrapMode: TextEdit.Wrap
         }
     }
diff --git a/meshroom/ui/qml/GraphEditor/TaskManager.qml b/meshroom/ui/qml/GraphEditor/TaskManager.qml
index 52fa209d59..aa48e43b24 100644
--- a/meshroom/ui/qml/GraphEditor/TaskManager.qml
+++ b/meshroom/ui/qml/GraphEditor/TaskManager.qml
@@ -39,7 +39,7 @@ Item {
 
     TextMetrics {
         id: nbMetrics
-        text: root.taskManager.nodes.count
+        text: root.taskManager ? root.taskManager.nodes.count : "0"
     }
 
     TextMetrics {
@@ -67,7 +67,7 @@ Item {
         anchors.fill: parent
         ScrollBar.vertical: ScrollBar {}
 
-        model: parent.taskManager.nodes
+        model: parent.taskManager ? parent.taskManager.nodes : null
         spacing: 3
 
         headerPositioning: ListView.OverlayHeader
diff --git a/meshroom/ui/qml/ImageGallery/ImageDelegate.qml b/meshroom/ui/qml/ImageGallery/ImageDelegate.qml
index bc5beb116b..484c172f6b 100644
--- a/meshroom/ui/qml/ImageGallery/ImageDelegate.qml
+++ b/meshroom/ui/qml/ImageGallery/ImageDelegate.qml
@@ -58,7 +58,7 @@ Item {
             }
             MenuItem {
                 text: "Define As Center Image"
-                property var activeNode: _reconstruction.activeNodes.get("SfMTransform").node
+                property var activeNode: _reconstruction ? _reconstruction.activeNodes.get("SfMTransform").node : null
                 enabled: !root.readOnly && _viewpoint.viewId != -1 && _reconstruction && activeNode
                 onClicked: activeNode.attribute("transformation").value = _viewpoint.viewId.toString()
             }
diff --git a/meshroom/ui/qml/ImageGallery/ImageGallery.qml b/meshroom/ui/qml/ImageGallery/ImageGallery.qml
index 52d088022f..3f2a58c2b9 100644
--- a/meshroom/ui/qml/ImageGallery/ImageGallery.qml
+++ b/meshroom/ui/qml/ImageGallery/ImageGallery.qml
@@ -35,7 +35,7 @@ Panel {
 
     QtObject {
         id: m
-        property variant currentCameraInit: _reconstruction.tempCameraInit ? _reconstruction.tempCameraInit : root.cameraInit
+        property variant currentCameraInit: _reconstruction && _reconstruction.tempCameraInit ? _reconstruction.tempCameraInit : root.cameraInit
         property variant viewpoints: currentCameraInit ? currentCameraInit.attribute('viewpoints').value : undefined
         property variant intrinsics: currentCameraInit ? currentCameraInit.attribute('intrinsics').value : undefined
         property bool readOnly: root.readOnly || displayHDR.checked
@@ -144,7 +144,7 @@ Panel {
     SensorDBDialog {
         id: sensorDBDialog
         sensorDatabase: cameraInit ? Filepath.stringToUrl(cameraInit.attribute("sensorDatabase").value) : ""
-        readOnly: _reconstruction.computing
+        readOnly: _reconstruction ? _reconstruction.computing : false
         onUpdateIntrinsicsRequest: _reconstruction.rebuildIntrinsics(cameraInit)
     }
 
@@ -273,11 +273,11 @@ Panel {
                         spacing: 2
 
                         property bool valid: Qt.isQtObject(object) // object can be evaluated to null at some point during creation/deletion
-                        property bool inViews: valid && _reconstruction.sfmReport && _reconstruction.isInViews(object)
+                        property bool inViews: valid && _reconstruction && _reconstruction.sfmReport && _reconstruction.isInViews(object)
 
                         // Camera Initialization indicator
                         IntrinsicsIndicator {
-                            intrinsic: parent.valid ? _reconstruction.getIntrinsic(object) : null
+                            intrinsic: parent.valid && _reconstruction ? _reconstruction.getIntrinsic(object) : null
                             metadata: imageDelegate.metadata
                         }
 
@@ -540,7 +540,7 @@ Panel {
 
         RowLayout {
             Layout.fillHeight: false
-            visible: root.cameraInits.count > 1
+            visible: root.cameraInits ? root.cameraInits.count > 1 : false
             Layout.alignment: Qt.AlignHCenter
             spacing: 2
 
@@ -560,8 +560,10 @@ Panel {
                     // display of group indices (real indices still are from
                     // 0 to cameraInits.count - 1)
                     var l = [];
-                    for (var i = 1; i <= root.cameraInits.count; i++) {
-                        l.push(i);
+                    if (root.cameraInits) {
+                        for (var i = 1; i <= root.cameraInits.count; i++) {
+                            l.push(i);
+                        }
                     }
                     return l;
                 }
@@ -569,13 +571,13 @@ Panel {
                 currentIndex: root.cameraInitIndex
                 onActivated: root.changeCurrentIndex(currentIndex)
             }
-            Label { text: "/ " + (root.cameraInits.count) }
+            Label { text: "/ " + (root.cameraInits ? root.cameraInits.count : "Unknown") }
             ToolButton {
                 text: MaterialIcons.navigate_next
                 font.family: MaterialIcons.fontFamily
                 ToolTip.text: "Next Group (Alt+Right)"
                 ToolTip.visible: hovered
-                enabled: nodesCB.currentIndex < root.cameraInits.count - 1
+                enabled: root.cameraInits ? nodesCB.currentIndex < root.cameraInits.count - 1 : false
                 onClicked: nodesCB.incrementCurrentIndex()
             }
         }
@@ -617,10 +619,10 @@ Panel {
             Layout.minimumWidth: childrenRect.width
             ToolTip.text: label + " Estimated Cameras"
             iconText: MaterialIcons.videocam
-            label: _reconstruction.nbCameras ? _reconstruction.nbCameras.toString() : "-"
+            label: _reconstruction && _reconstruction.nbCameras ? _reconstruction.nbCameras.toString() : "-"
             padding: 3
 
-            enabled: _reconstruction.cameraInit && _reconstruction.nbCameras
+            enabled: _reconstruction ? _reconstruction.cameraInit && _reconstruction.nbCameras : false
             checkable: true
             checked: false
 
@@ -646,10 +648,10 @@ Panel {
             Layout.minimumWidth: childrenRect.width
             ToolTip.text: label + " Non Estimated Cameras"
             iconText: MaterialIcons.videocam_off
-            label: _reconstruction.nbCameras ? ((m.viewpoints ? m.viewpoints.count : 0) - _reconstruction.nbCameras.toString()).toString() : "-"
+            label: _reconstruction && _reconstruction.nbCameras ? ((m.viewpoints ? m.viewpoints.count : 0) - _reconstruction.nbCameras.toString()).toString() : "-"
             padding: 3
 
-            enabled: _reconstruction.cameraInit && _reconstruction.nbCameras
+            enabled: _reconstruction ? _reconstruction.cameraInit && _reconstruction.nbCameras : false
             checkable: true
             checked: false
 
@@ -704,7 +706,7 @@ Panel {
         MaterialToolLabelButton {
             id: displayHDR
             Layout.minimumWidth: childrenRect.width
-            property var activeNode: _reconstruction.activeNodes.get("LdrToHdrMerge").node
+            property var activeNode: _reconstruction ? _reconstruction.activeNodes.get("LdrToHdrMerge").node : null
             ToolTip.text: "Visualize HDR images: " + (activeNode ? activeNode.label : "No Node")
             iconText: MaterialIcons.filter
             label: activeNode ? activeNode.attribute("nbBrackets").value : ""
@@ -747,7 +749,7 @@ Panel {
             id: imageProcessing
             Layout.minimumWidth: childrenRect.width
 
-            property var activeNode: _reconstruction.activeNodes.get("ImageProcessing").node
+            property var activeNode: _reconstruction ? _reconstruction.activeNodes.get("ImageProcessing").node : null
             font.pointSize: 15
             padding: 0
             ToolTip.text: "Preprocessed Images: " + (activeNode ? activeNode.label : "No Node")
diff --git a/meshroom/ui/qml/LiveSfmView.qml b/meshroom/ui/qml/LiveSfmView.qml
index b8190de99a..8062859a1b 100644
--- a/meshroom/ui/qml/LiveSfmView.qml
+++ b/meshroom/ui/qml/LiveSfmView.qml
@@ -13,7 +13,7 @@ Panel {
     id: root
 
     property variant reconstruction
-    readonly property variant liveSfmManager: reconstruction.liveSfmManager
+    readonly property variant liveSfmManager: reconstruction ? reconstruction.liveSfmManager : null
 
     title: "Live Reconstruction"
     icon: Label {
@@ -41,7 +41,7 @@ Panel {
             width: parent.width
             GroupBox {
                 Layout.fillWidth: true
-                enabled: !liveSfmManager.running
+                enabled: liveSfmManager ? !liveSfmManager.running : false
 
                 GridLayout {
                     width: parent.width
@@ -59,7 +59,7 @@ Panel {
                             id: folderPath
                             Layout.fillWidth: true
                             selectByMouse: true
-                            text: liveSfmManager.folder
+                            text: liveSfmManager ? liveSfmManager.folder : ""
                             placeholderText: "Select a Folder"
                         }
                         ToolButton {
@@ -90,8 +90,8 @@ Panel {
             Button {                
                 Layout.alignment: Qt.AlignCenter
                 text: checked ? "Stop" : "Start"
-                enabled: liveSfmManager.running || folderPath.text.trim() != ''
-                checked: liveSfmManager.running
+                enabled: liveSfmManager ? liveSfmManager.running || folderPath.text.trim() != '' : false
+                checked: liveSfmManager ? liveSfmManager.running : false
                 onClicked: {
                     if(!liveSfmManager.running)
                         liveSfmManager.start(folderPath.text, minImg_SB.value)
diff --git a/meshroom/ui/qml/Viewer/Viewer2D.qml b/meshroom/ui/qml/Viewer/Viewer2D.qml
index c2db199bf6..12a6794659 100644
--- a/meshroom/ui/qml/Viewer/Viewer2D.qml
+++ b/meshroom/ui/qml/Viewer/Viewer2D.qml
@@ -24,7 +24,7 @@ FocusScope {
     property alias useLensDistortionViewer: displayLensDistortionViewer.checked
     property alias usePanoramaViewer: displayPanoramaViewer.checked
 
-    property var activeNodeFisheye: _reconstruction.activeNodes.get("PanoramaInit").node
+    property var activeNodeFisheye: _reconstruction ? _reconstruction.activeNodes.get("PanoramaInit").node : null
     property bool cropFisheye : activeNodeFisheye ? activeNodeFisheye.attribute("useFisheye").value : false
     property bool enable8bitViewer: MeshroomApp.default8bitViewerEnabled
 
@@ -202,15 +202,15 @@ FocusScope {
         if (useExternal) {
             return sourceExternal;
         }
-        if (!displayedNode || outputAttribute.name == "gallery") {
+        if (_reconstruction && (!displayedNode || outputAttribute.name == "gallery")) {
             return getViewpointPath(_reconstruction.selectedViewId);
         } 
-        return getFileAttributePath(displayedNode, outputAttribute.name, _reconstruction.selectedViewId);
+        return getFileAttributePath(displayedNode, outputAttribute.name, _reconstruction ? _reconstruction.selectedViewId : -1);
     }
 
     function getMetadata() {
         // entry point for getting the image metadata
-        if (useExternal) {
+        if (useExternal || !_reconstruction) {
             return {};
         } else {
             return getViewpointMetadata(_reconstruction.selectedViewId);
@@ -220,6 +220,8 @@ FocusScope {
     function getFileAttributePath(node, attrName, viewId) {
         // get output attribute with matching name
         // and parse its value to get the image filepath
+        if (!node)
+            return "";
         for (var i = 0; i < node.attributes.count; i++) {
             var attr = node.attributes.at(i);
             if (attr.name == attrName) {
@@ -429,7 +431,7 @@ FocusScope {
                                 'sfmRequired': Qt.binding(function(){ return displayLensDistortionViewer.checked ? true : false;}),
                                 'surface.msfmData': Qt.binding(function() { return (msfmDataLoader.status === Loader.Ready && msfmDataLoader.item != null && msfmDataLoader.item.status === 2) ? msfmDataLoader.item : null; }),
                                 'canBeHovered': false,
-                                'idView': Qt.binding(function() { return _reconstruction.selectedViewId; }),
+                                'idView': Qt.binding(function() { return (_reconstruction ? _reconstruction.selectedViewId : -1); }),
                                 'cropFisheye': false
                                 })
                           } else {
@@ -521,7 +523,7 @@ FocusScope {
                 Loader {
                     id: featuresViewerLoader
                     active: displayFeatures.checked
-                    property var activeNode: _reconstruction.activeNodes.get("FeatureExtraction").node
+                    property var activeNode: _reconstruction ? _reconstruction.activeNodes.get("FeatureExtraction").node : null
 
                     // handle rotation/position based on available metadata
                     rotation: {
@@ -554,7 +556,7 @@ FocusScope {
                 // note: use a Loader to evaluate if a PanoramaInit node exist and displayFisheyeCircle checked at runtime
                 Loader {
                     anchors.centerIn: parent
-                    property var activeNode: _reconstruction.activeNodes.get("PanoramaInit").node
+                    property var activeNode: _reconstruction ? _reconstruction.activeNodes.get("PanoramaInit").node : null
                     active: (displayFisheyeCircleLoader.checked && activeNode)
 
                     // handle rotation/position based on available metadata
@@ -602,7 +604,7 @@ FocusScope {
                 Loader {
                     id: colorCheckerViewerLoader
                     anchors.centerIn: parent
-                    property var activeNode: _reconstruction.activeNodes.get("ColorCheckerDetection").node
+                    property var activeNode: _reconstruction ? _reconstruction.activeNodes.get("ColorCheckerDetection").node : null
                     active: (displayColorCheckerViewerLoader.checked && activeNode)
 
 
@@ -706,7 +708,7 @@ FocusScope {
                         id: mfeaturesLoader
 
                         property bool isUsed: displayFeatures.checked
-                        property var activeNode: root.aliceVisionPluginAvailable ? _reconstruction.activeNodes.get("FeatureExtraction").node : null
+                        property var activeNode: root.aliceVisionPluginAvailable && _reconstruction ? _reconstruction.activeNodes.get("FeatureExtraction").node : null
                         property bool isComputed: activeNode && activeNode.isComputed
                         active: false
 
@@ -749,7 +751,7 @@ FocusScope {
                             }
                             // For lens distortion viewer: use all nodes creating a sfmData file
                             var nodeType = displayLensDistortionViewer.checked ? 'sfmData' : 'sfm'
-                            var sfmNode = _reconstruction.activeNodes.get(nodeType).node
+                            var sfmNode = _reconstruction ? _reconstruction.activeNodes.get(nodeType).node : null
                             if(sfmNode === null){
                                 return null
                             }
@@ -827,7 +829,7 @@ FocusScope {
                         id: mtracksLoader
 
                         property bool isUsed: displayFeatures.checked || displaySfmStatsView.checked || displaySfmDataGlobalStats.checked || displayPanoramaViewer.checked
-                        property var activeNode: root.aliceVisionPluginAvailable ? _reconstruction.activeNodes.get('FeatureMatching').node : null
+                        property var activeNode: root.aliceVisionPluginAvailable && _reconstruction ? _reconstruction.activeNodes.get('FeatureMatching').node : null
                         property bool isComputed: activeNode && activeNode.isComputed
 
                         active: false
@@ -921,7 +923,7 @@ FocusScope {
                         id: ldrHdrCalibrationGraph
                         anchors.fill: parent
 
-                        property var activeNode: _reconstruction.activeNodes.get('LdrToHdrCalibration').node
+                        property var activeNode: _reconstruction ? _reconstruction.activeNodes.get('LdrToHdrCalibration').node : null
                         property var isEnabled: displayLdrHdrCalibrationGraph.checked && activeNode && activeNode.isComputed
                         // active: isEnabled
                         // Setting "active" from true to false creates a crash on linux with Qt 5.14.2.
@@ -995,7 +997,7 @@ FocusScope {
                         }
                         MaterialToolButton {
                             id: displayLensDistortionViewer
-                            property var activeNode: root.aliceVisionPluginAvailable ? _reconstruction.activeNodes.get('sfmData').node : null
+                            property var activeNode: root.aliceVisionPluginAvailable && _reconstruction ? _reconstruction.activeNodes.get('sfmData').node : null
                             property bool isComputed: {
                                 if(!activeNode)
                                     return false;
@@ -1031,7 +1033,7 @@ FocusScope {
                         }
                         MaterialToolButton {
                             id: displayPanoramaViewer
-                            property var activeNode: root.aliceVisionPluginAvailable ? _reconstruction.activeNodes.get('SfMTransform').node : null
+                            property var activeNode: root.aliceVisionPluginAvailable && _reconstruction ? _reconstruction.activeNodes.get('SfMTransform').node : null
                             property bool isComputed: {
                                 if(!activeNode)
                                     return false;
@@ -1083,7 +1085,7 @@ FocusScope {
                         }
                         MaterialToolButton {
                             id: displayFisheyeCircleLoader
-                            property var activeNode: _reconstruction.activeNodes.get('PanoramaInit').node
+                            property var activeNode: _reconstruction ? _reconstruction.activeNodes.get('PanoramaInit').node : null
                             ToolTip.text: "Display Fisheye Circle: " + (activeNode ? activeNode.label : "No Node")
                             text: MaterialIcons.vignette
                             // text: MaterialIcons.panorama_fish_eye
@@ -1096,7 +1098,7 @@ FocusScope {
                         }
                         MaterialToolButton {
                             id: displayColorCheckerViewerLoader
-                            property var activeNode: _reconstruction.activeNodes.get('ColorCheckerDetection').node
+                            property var activeNode: _reconstruction ? _reconstruction.activeNodes.get('ColorCheckerDetection').node : null
                             ToolTip.text: "Display Color Checker: " + (activeNode ? activeNode.label : "No Node")
                             text: MaterialIcons.view_comfy //view_module grid_on gradient view_comfy border_all
                             font.pointSize: 11
@@ -1121,7 +1123,7 @@ FocusScope {
 
                         MaterialToolButton {
                             id: displayLdrHdrCalibrationGraph
-                            property var activeNode: _reconstruction.activeNodes.get("LdrToHdrCalibration").node
+                            property var activeNode: _reconstruction ? _reconstruction.activeNodes.get("LdrToHdrCalibration").node : null
                             property bool isComputed: activeNode && activeNode.isComputed
                             ToolTip.text: "Display Camera Response Function: " + (activeNode ? activeNode.label : "No Node")
                             text: MaterialIcons.timeline
@@ -1166,7 +1168,7 @@ FocusScope {
                         }
 
                         MaterialToolButton {
-                            property var activeNode: root.oiioPluginAvailable ? _reconstruction.activeNodes.get('allDepthMap').node : null
+                            property var activeNode: root.oiioPluginAvailable && _reconstruction ? _reconstruction.activeNodes.get('allDepthMap').node : null
                             enabled: activeNode
                             ToolTip.text: "View Depth Map in 3D (" + (activeNode ? activeNode.label : "No DepthMap Node Selected") + ")"
                             text: MaterialIcons.input
@@ -1180,7 +1182,7 @@ FocusScope {
 
                         MaterialToolButton {
                             id: displaySfmStatsView
-                            property var activeNode: root.aliceVisionPluginAvailable ? _reconstruction.activeNodes.get('sfm').node : null
+                            property var activeNode: root.aliceVisionPluginAvailable && _reconstruction ? _reconstruction.activeNodes.get('sfm').node : null
 
                             font.family: MaterialIcons.fontFamily
                             text: MaterialIcons.assessment
@@ -1205,7 +1207,7 @@ FocusScope {
 
                         MaterialToolButton {
                             id: displaySfmDataGlobalStats
-                            property var activeNode: root.aliceVisionPluginAvailable ? _reconstruction.activeNodes.get('sfm').node : null
+                            property var activeNode: root.aliceVisionPluginAvailable && _reconstruction ? _reconstruction.activeNodes.get('sfm').node : null
 
                             font.family: MaterialIcons.fontFamily
                             text: MaterialIcons.language
diff --git a/meshroom/ui/qml/Viewer3D/AlembicLoader.qml b/meshroom/ui/qml/Viewer3D/AlembicLoader.qml
index 9b8bbf5f33..0dc564622c 100644
--- a/meshroom/ui/qml/Viewer3D/AlembicLoader.qml
+++ b/meshroom/ui/qml/Viewer3D/AlembicLoader.qml
@@ -64,7 +64,7 @@ AlembicEntity {
                 */
                 PhongMaterial{
                     id: mat
-                    ambient: viewId === _reconstruction.selectedViewId ? activePalette.highlight : customColor // "#CCC"
+                    ambient: _reconstruction && viewId === _reconstruction.selectedViewId ? activePalette.highlight : customColor // "#CCC"
                     diffuse: cameraPicker.containsMouse ? Qt.lighter(activePalette.highlight, 1.2) : ambient
                 },
                 ObjectPicker {
diff --git a/meshroom/ui/qml/Viewer3D/Inspector3D.qml b/meshroom/ui/qml/Viewer3D/Inspector3D.qml
index 7e4ac47231..5f219c9e56 100644
--- a/meshroom/ui/qml/Viewer3D/Inspector3D.qml
+++ b/meshroom/ui/qml/Viewer3D/Inspector3D.qml
@@ -112,7 +112,7 @@ FloatingPane {
                     // Synchronization
                     MaterialToolButton {
                         id: syncViewpointCamera
-                        enabled: _reconstruction.sfmReport
+                        enabled: _reconstruction ? _reconstruction.sfmReport : false
                         text: MaterialIcons.linked_camera
                         ToolTip.text: "Sync with Image Selection"
                         checked: enabled && Viewer3DSettings.syncViewpointCamera
@@ -200,8 +200,8 @@ FloatingPane {
                     // add mediaLibrary.count in the binding to ensure 'entity'
                     // is re-evaluated when mediaLibrary delegates are modified
                     property bool loading: model.status === SceneLoader.Loading
-                    property bool hovered:  model.attribute ? uigraph.hoveredNode === model.attribute.node : containsMouse
-                    property bool isSelectedNode: model.attribute ? uigraph.selectedNode === model.attribute.node : false
+                    property bool hovered:  model.attribute ? (uigraph ? uigraph.hoveredNode === model.attribute.node : false) : containsMouse
+                    property bool isSelectedNode: model.attribute ? (uigraph ? uigraph.selectedNode === model.attribute.node : false) : false
 
                     onIsSelectedNodeChanged: updateCurrentIndex()
 
diff --git a/meshroom/ui/qml/Viewer3D/Viewer3D.qml b/meshroom/ui/qml/Viewer3D/Viewer3D.qml
index 5e0e390fb4..89b46274cd 100644
--- a/meshroom/ui/qml/Viewer3D/Viewer3D.qml
+++ b/meshroom/ui/qml/Viewer3D/Viewer3D.qml
@@ -26,7 +26,7 @@ FocusScope {
     readonly property vector3d defaultCamUpVector: Qt.vector3d(0.0, 1.0, 0.0)
     readonly property vector3d defaultCamViewCenter: Qt.vector3d(0.0, 0.0, 0.0)
 
-    readonly property var viewpoint: _reconstruction.selectedViewpoint
+    readonly property var viewpoint: _reconstruction ? _reconstruction.selectedViewpoint : null
     readonly property bool doSyncViewpointCamera: Viewer3DSettings.syncViewpointCamera && (viewpoint && viewpoint.isReconstructed)
 
     // functions
diff --git a/meshroom/ui/qml/WorkspaceView.qml b/meshroom/ui/qml/WorkspaceView.qml
index 2c4d6ae273..9379da77e9 100644
--- a/meshroom/ui/qml/WorkspaceView.qml
+++ b/meshroom/ui/qml/WorkspaceView.qml
@@ -20,7 +20,7 @@ Item {
     id: root
 
     property variant reconstruction: _reconstruction
-    readonly property variant cameraInits: _reconstruction.cameraInits
+    readonly property variant cameraInits: _reconstruction ? _reconstruction.cameraInits : null
     property bool readOnly: false
     property alias panel3dViewer: panel3dViewerLoader.item
     readonly property Viewer2D viewer2D: viewer2D
@@ -50,7 +50,7 @@ Item {
 
     // Load reconstruction's current SfM file
     function viewSfM() {
-        var activeNode = _reconstruction.activeNodes.get('sfm').node;
+        var activeNode = _reconstruction.activeNodes ? _reconstruction.activeNodes.get('sfm').node : null;
         if(!activeNode)
             return;
         if(panel3dViewerLoader.active) {
@@ -75,9 +75,9 @@ Item {
                 Layout.fillHeight: true
                 readOnly: root.readOnly
                 cameraInits: root.cameraInits
-                cameraInit: reconstruction.cameraInit
-                tempCameraInit: reconstruction.tempCameraInit
-                cameraInitIndex: reconstruction.cameraInitIndex
+                cameraInit: reconstruction ? reconstruction.cameraInit : null
+                tempCameraInit: reconstruction ? reconstruction.tempCameraInit : null
+                cameraInitIndex: reconstruction ? reconstruction.cameraInitIndex : -1
                 onRemoveImageRequest: reconstruction.removeAttribute(attribute)
                 onFilesDropped: reconstruction.handleFilesDrop(drop, augmentSfm ? null : cameraInit)
             }
@@ -208,7 +208,7 @@ Item {
                         
                         // Load reconstructed model
                         Button {
-                            readonly property var outputAttribute: _reconstruction.texturing ? _reconstruction.texturing.attribute("outputMesh") : null
+                            readonly property var outputAttribute: _reconstruction && _reconstruction.texturing ? _reconstruction.texturing.attribute("outputMesh") : null
                             readonly property bool outputReady: outputAttribute && _reconstruction.texturing.globalStatus === "SUCCESS"
                             readonly property int outputMediaIndex: c_viewer3D.library.find(outputAttribute)
 
diff --git a/meshroom/ui/qml/main.qml b/meshroom/ui/qml/main.qml
index a0a4071d8c..0c9f26d7e4 100755
--- a/meshroom/ui/qml/main.qml
+++ b/meshroom/ui/qml/main.qml
@@ -24,8 +24,8 @@ ApplicationWindow {
     visible: true
 
     title: {
-        var t = (_reconstruction.graph && _reconstruction.graph.filepath) ? _reconstruction.graph.filepath : "Untitled"
-        if(!_reconstruction.undoStack.clean)
+        var t = (_reconstruction && _reconstruction.graph && _reconstruction.graph.filepath) ? _reconstruction.graph.filepath : "Untitled"
+        if (_reconstruction && !_reconstruction.undoStack.clean)
             t += "*"
         t += " - " + Qt.application.name + " " + Qt.application.version
         return t
@@ -73,12 +73,12 @@ ApplicationWindow {
 
         property var _callback: undefined
 
-        title: Filepath.basename(_reconstruction.graph.filepath) || "Unsaved Project"
+        title: (_reconstruction ? Filepath.basename(_reconstruction.graph.filepath) : "") || "Unsaved Project"
         preset: "Info"
         canCopy: false
-        text: _reconstruction.graph.filepath ? "Current project has unsaved modifications."
+        text: _reconstruction && _reconstruction.graph.filepath ? "Current project has unsaved modifications."
                                              : "Current project has not been saved."
-        helperText: _reconstruction.graph.filepath ? "Would you like to save those changes?"
+        helperText: _reconstruction && _reconstruction.graph.filepath ? "Would you like to save those changes?"
                                                    : "Would you like to save this project?"
 
         standardButtons: Dialog.Save | Dialog.Cancel | Dialog.Discard
@@ -165,14 +165,18 @@ ApplicationWindow {
         property bool warnIfUnsaved: true
 
         // evaluate if global reconstruction computation can be started
-        property bool canStartComputation: _reconstruction.viewpoints.count >= 2      // at least 2 images
-                                           && !_reconstruction.computing              // computation is not started
-                                           && _reconstruction.graph.canComputeLeaves  // graph has no uncomputable nodes
+        property bool canStartComputation: _reconstruction ?
+                                           _reconstruction.viewpoints.count >= 2       // at least 2 images
+                                           && !_reconstruction.computing               // computation is not started
+                                           && _reconstruction.graph.canComputeLeaves : // graph has no uncomputable nodes
+                                           false
 
         // evaluate if graph computation can be submitted externally
-        property bool canSubmit: _reconstruction.canSubmit                            // current setup allows to compute externally
-                                 && canStartComputation                               // can be computed
-                                 && _reconstruction.graph.filepath                    // graph is saved on disk
+        property bool canSubmit: _reconstruction ?
+                                 _reconstruction.canSubmit                             // current setup allows to compute externally
+                                 && canStartComputation                                // can be computed
+                                 && _reconstruction.graph.filepath :                   // graph is saved on disk
+                                 false
 
         function compute(node, force) {
             if(!force && warnIfUnsaved && !_reconstruction.graph.filepath)
@@ -276,7 +280,7 @@ ApplicationWindow {
             preset: "Warning"
             title: "Unsaved Project"
             text: "Data will be computed in the default cache folder if project remains unsaved."
-            detailedText: "Default cache folder: " + _reconstruction.graph.cacheDir
+            detailedText: "Default cache folder: " + (_reconstruction ? _reconstruction.graph.cacheDir : "unknown")
             helperText: "Save project first?"
             standardButtons: Dialog.Discard | Dialog.Cancel | Dialog.Save
 
@@ -377,7 +381,7 @@ ApplicationWindow {
         // is busy building intrinsics while importing images
         id: buildingIntrinsicsDialog
         modal: true
-        visible: _reconstruction.buildingIntrinsics
+        visible: _reconstruction ? _reconstruction.buildingIntrinsics : false
         closePolicy: Popup.NoAutoClose
         title: "Initializing Cameras"
         icon.text: MaterialIcons.camera
@@ -404,19 +408,19 @@ ApplicationWindow {
     Action {
         id: undoAction
 
-        property string tooltip: 'Undo "' +_reconstruction.undoStack.undoText +'"'
+        property string tooltip: 'Undo "' + (_reconstruction ? _reconstruction.undoStack.undoText : "Unknown") + '"'
         text: "Undo"
         shortcut: "Ctrl+Z"
-        enabled: _reconstruction.undoStack.canUndo && _reconstruction.undoStack.isUndoableIndex
+        enabled: _reconstruction ? _reconstruction.undoStack.canUndo && _reconstruction.undoStack.isUndoableIndex : false
         onTriggered: _reconstruction.undoStack.undo()
     }
     Action {
         id: redoAction
 
-        property string tooltip: 'Redo "' +_reconstruction.undoStack.redoText +'"'
+        property string tooltip: 'Redo "' + (_reconstruction ? _reconstruction.undoStack.redoText : "Unknown") + '"'
         text: "Redo"
         shortcut: "Ctrl+Shift+Z"
-        enabled: _reconstruction.undoStack.canRedo && !_reconstruction.undoStack.lockedRedo
+        enabled: _reconstruction ? _reconstruction.undoStack.canRedo && !_reconstruction.undoStack.lockedRedo : false
         onTriggered: _reconstruction.undoStack.redo()
     }
     Action {
@@ -424,16 +428,18 @@ ApplicationWindow {
 
         property string tooltip: {
             var s = "Copy selected node"
-            s += (_reconstruction.selectedNodes.count > 1 ? "s (" : " (") + getSelectedNodesName()
+            s += (_reconstruction && _reconstruction.selectedNodes.count > 1 ? "s (" : " (") + getSelectedNodesName()
             s += ") to the clipboard"
             return s
         }
-        text: "Copy Node" + (_reconstruction.selectedNodes.count > 1 ? "s " : " ")
-        enabled: _reconstruction.selectedNodes.count > 0
+        text: "Copy Node" + (_reconstruction && _reconstruction.selectedNodes.count > 1 ? "s " : " ")
+        enabled: _reconstruction ? _reconstruction.selectedNodes.count > 0 : false
         onTriggered: graphEditor.copyNodes()
 
         function getSelectedNodesName()
         {
+            if (!_reconstruction)
+                return ""
             var nodesName = ""
             for (var i = 0; i < _reconstruction.selectedNodes.count; i++)
             {
@@ -612,7 +618,7 @@ ApplicationWindow {
                 id: saveAction
                 text: "Save"
                 shortcut: "Ctrl+S"
-                enabled: (_reconstruction.graph && !_reconstruction.graph.filepath) || !_reconstruction.undoStack.clean
+                enabled: _reconstruction ? (_reconstruction.graph && !_reconstruction.graph.filepath) || !_reconstruction.undoStack.clean : false
                 onTriggered: {
                     if(_reconstruction.graph.filepath) {
                         _reconstruction.save()
@@ -742,7 +748,7 @@ ApplicationWindow {
             TextField {
                 readOnly: true
                 selectByMouse: true
-                text: _reconstruction.graph.cacheDir
+                text: _reconstruction ? _reconstruction.graph.cacheDir : "Unknown"
                 color: Qt.darker(palette.text, 1.2)
                 background: Item {}
             }
@@ -809,12 +815,12 @@ ApplicationWindow {
                     }
                     Button {
                         text: "Stop"
-                        enabled: _reconstruction.computingLocally
+                        enabled: _reconstruction ? _reconstruction.computingLocally : false
                         onClicked: _reconstruction.stopExecution()
                     }
                     Item { width: 20; height: 1 }
                     Button {
-                        visible: _reconstruction.canSubmit
+                        visible: _reconstruction ? _reconstruction.canSubmit : false
                         text: "Submit"
                         onClicked: computeManager.submit(null)
                     }
@@ -839,7 +845,7 @@ ApplicationWindow {
                 id: chunksListView
                 Layout.fillWidth: true
                 height: 6
-                model: _reconstruction.sortedDFSChunks
+                model: _reconstruction ? _reconstruction.sortedDFSChunks : null
             }
 
             WorkspaceView {
@@ -848,7 +854,7 @@ ApplicationWindow {
                 Layout.fillHeight: true
                 Layout.minimumHeight: 50
                 reconstruction: _reconstruction
-                readOnly: _reconstruction.computing
+                readOnly: _reconstruction ? _reconstruction.computing : false
 
                 function viewNode(node, mouse) {
                     // 2D viewer
@@ -899,7 +905,7 @@ ApplicationWindow {
                             updatingStatus = false
                         }
                         property bool updatingStatus: false
-                        enabled: !updatingStatus && !_reconstruction.computingLocally
+                        enabled: !updatingStatus && (_reconstruction ? !_reconstruction.computingLocally : false)
                     }
                     MaterialToolButton {
                         text: MaterialIcons.more_vert
@@ -914,7 +920,7 @@ ApplicationWindow {
                             x: -width + parent.width
                             MenuItem {
                                 text: "Clear Pending Status"
-                                enabled: !_reconstruction.computingLocally
+                                enabled: _reconstruction ? !_reconstruction.computingLocally : false
                                 onTriggered: _reconstruction.graph.clearSubmittedNodes()
                             }
                             MenuItem {
@@ -948,7 +954,7 @@ ApplicationWindow {
                     visible: graphEditorPanel.currentTab === 1
 
                     uigraph: _reconstruction
-                    taskManager: _reconstruction.taskManager
+                    taskManager: _reconstruction ? _reconstruction.taskManager : null
 
                     anchors.fill: parent
                 }
@@ -958,8 +964,8 @@ ApplicationWindow {
             NodeEditor {
                 id: nodeEditor
                 width: Math.round(parent.width * 0.3)
-                node: _reconstruction.selectedNode
-                property bool computing: _reconstruction.computing
+                node: _reconstruction ? _reconstruction.selectedNode : null
+                property bool computing: _reconstruction ? _reconstruction.computing : false
                 // Make NodeEditor readOnly when computing
                 readOnly: node ? node.locked : false