diff --git a/modules/ui/BaseTrainUIView.py b/modules/ui/BaseTrainUIView.py
index ff3acd2b7..c698c051c 100644
--- a/modules/ui/BaseTrainUIView.py
+++ b/modules/ui/BaseTrainUIView.py
@@ -53,7 +53,10 @@ def show_window(self, window): pass
     def connect_window_closed(self, window, callback): pass
 
     def sync_cloud_secrets(self):
-        self.ui_state.get_var("secrets.cloud").update(self.controller.train_config.secrets.cloud)
+        # Called from training thread — defer to main thread
+        self.schedule_on_main_thread(
+            lambda: self.ui_state.get_var("secrets.cloud").update(self.controller.train_config.secrets.cloud)
+        )
 
     def start_training(self):
         self.controller.start_training()
diff --git a/modules/ui/PySide6VideoToolUIView.py b/modules/ui/PySide6VideoToolUIView.py
index 71b442dcf..18772adf6 100644
--- a/modules/ui/PySide6VideoToolUIView.py
+++ b/modules/ui/PySide6VideoToolUIView.py
@@ -6,7 +6,7 @@
 from modules.util.ui.PySide6UIState import PySide6UIState
 
 from PIL.ImageQt import ImageQt
-from PySide6.QtCore import Qt
+from PySide6.QtCore import Qt, QTimer
 from PySide6.QtGui import QPixmap
 from PySide6.QtWidgets import (
     QDialog,
@@ -112,14 +112,22 @@ def _create_textbox(self, master, row, col, width, height, ui_state, var_name):
         widget.textChanged.connect(lambda: var.set(widget.toPlainText()))
         return widget
 
+    def schedule_on_main_thread(self, fn):
+        QTimer.singleShot(0, self, fn)
+
     def update_status(self, status_text: str):
-        self._status_box.append(status_text)
+        # Called from the video tool's worker thread — defer to main thread
+        self.schedule_on_main_thread(lambda: self._status_box.append(status_text))
 
     def clear_status(self):
         self._status_box.clear()
 
     def update_preview(self, preview_image, label_text: str):
+        # Called from the video tool's worker thread — defer to main thread
         pixmap = QPixmap.fromImage(ImageQt(preview_image.convert("RGBA")))
+        self.schedule_on_main_thread(lambda: self._do_update_preview(pixmap, label_text))
+
+    def _do_update_preview(self, pixmap: QPixmap, label_text: str):
         self._preview_label.setPixmap(
             pixmap.scaled(150, 150, Qt.KeepAspectRatio, Qt.SmoothTransformation)
         )