diff --git a/src/libstore/filetransfer.cc b/src/libstore/filetransfer.cc
index f7a5d672103..240d5aa9370 100644
--- a/src/libstore/filetransfer.cc
+++ b/src/libstore/filetransfer.cc
@@ -962,19 +962,32 @@ struct curlFileTransfer : public FileTransfer
         writeFull(wakeupPipe.writeSide.get(), " ");
 #endif
 
-        return ItemHandle(static_cast<Item &>(*item));
+        return ItemHandle(ref<Item>(std::move(item)));
     }
 
-    ItemHandle enqueueFileTransfer(const FileTransferRequest & request, Callback<FileTransferResult> callback) override
+    ItemHandle
+    enqueueFileTransfer(const FileTransferRequest & request, Callback<FileTransferResult> callback) noexcept override
     {
         /* Handle s3:// URIs by converting to HTTPS and optionally adding auth */
         if (request.uri.scheme() == "s3") {
             auto modifiedRequest = request;
             modifiedRequest.setupForS3();
-            return enqueueItem(make_ref<TransferItem>(*this, std::move(modifiedRequest), std::move(callback)));
+            auto item = make_ref<TransferItem>(*this, std::move(modifiedRequest), std::move(callback));
+            try {
+                return enqueueItem(item);
+            } catch (const nix::Error & e) {
+                item->fail(e);
+                return ItemHandle(ref<Item>(std::move(item)));
+            }
         }
 
-        return enqueueItem(make_ref<TransferItem>(*this, request, std::move(callback)));
+        auto item = make_ref<TransferItem>(*this, request, std::move(callback));
+        try {
+            return enqueueItem(item);
+        } catch (const nix::Error & e) {
+            item->fail(e);
+            return ItemHandle(ref<Item>(std::move(item)));
+        }
     }
 
     void unpauseTransfer(ref<TransferItem> item)
@@ -988,7 +1001,7 @@ struct curlFileTransfer : public FileTransfer
 
     void unpauseTransfer(ItemHandle handle) override
     {
-        unpauseTransfer(ref{static_cast<TransferItem &>(handle.item.get()).shared_from_this()});
+        unpauseTransfer(ref{static_cast<TransferItem &>(*handle.item).shared_from_this()});
     }
 };
 
@@ -1047,7 +1060,7 @@ void FileTransferRequest::setupForS3()
 #endif
 }
 
-std::future<FileTransferResult> FileTransfer::enqueueFileTransfer(const FileTransferRequest & request)
+std::future<FileTransferResult> FileTransfer::enqueueFileTransfer(const FileTransferRequest & request) noexcept
 {
     auto promise = std::make_shared<std::promise<FileTransferResult>>();
     enqueueFileTransfer(request, {[promise](std::future<FileTransferResult> fut) {
diff --git a/src/libstore/include/nix/store/filetransfer.hh b/src/libstore/include/nix/store/filetransfer.hh
index fa8a649e2b3..9220c26cb0d 100644
--- a/src/libstore/include/nix/store/filetransfer.hh
+++ b/src/libstore/include/nix/store/filetransfer.hh
@@ -262,11 +262,11 @@ public:
      */
     struct ItemHandle
     {
-        std::reference_wrapper<Item> item;
+        ref<Item> item;
         friend struct FileTransfer;
 
-        ItemHandle(Item & item)
-            : item(item)
+        explicit ItemHandle(ref<Item> item)
+            : item(std::move(item))
         {
         }
     };
@@ -279,14 +279,14 @@ public:
      * exception.
      */
     virtual ItemHandle
-    enqueueFileTransfer(const FileTransferRequest & request, Callback<FileTransferResult> callback) = 0;
+    enqueueFileTransfer(const FileTransferRequest & request, Callback<FileTransferResult> callback) noexcept = 0;
 
     /**
      * Unpause a transfer that has been previously paused by a dataCallback.
      */
     virtual void unpauseTransfer(ItemHandle handle) = 0;
 
-    std::future<FileTransferResult> enqueueFileTransfer(const FileTransferRequest & request);
+    std::future<FileTransferResult> enqueueFileTransfer(const FileTransferRequest & request) noexcept;
 
     /**
      * Synchronously download a file.