Blocks Tutorial: Simulator Stuck Loading and Workspace Becomes Blank After Completing All Tutorial Steps

[Nina-1210]

Describe the bug
After completing all steps in a longer Blocks tutorial, the simulator gets stuck loading and the workspace becomes blank. The issue persists after reopening the project and is resolved only by refreshing the page.

Note: This issue is intermittent but occurs frequently in tutorials such as Micro Chat and Pet Hamster.

Steps to reproduce the behavior:

1. Navigate to Microsoft MakeCode for micro:bit.
2. Open a large Blocks Start tutorial (for example, Micro Chat or Pet Hamster).
3. Complete all tutorial steps.
4. Click the "Done" button.
5. Observe the simulator and editor workspace.

Actual behavior
The simulator remains stuck in a loading state and Blocks workspace becomes blank and no project content is displayed.

Expected behavior
After completing the tutorial, the simulator and Blocks workspace should continue to display the completed project correctly without requiring a page refresh.

Screenshots

Additional context
1.OS: Windows 11 25H2 & Mac Mini M2 macOS Tahoe 26.5.2
2.Browser: Chrome, Edge, Firefox, and Safari
3.makecode.microbit.org version: 9.0.2
4.Microsoft MakeCode version: 13.0.2

[Jaqster]

I just reproed this too -

[jwunderl]

@Jaqster question on this, are you still able to reproduce this / any chance it was from browser session updating to new version? Have been trying to reproduce it while finishing up other bugs without success. Have cleared up other issues so just going to read through the code that runs between clicking done and loading up the new tutorial to see where this could be (since loading up blank workspace but being there when you refresh narrows down a good bit

[Jaqster]

No, I tried a dozen times, and now I can't repro! Not sure if this was just a blip... Let's ignore for now until we can get a reliable repro or have someone else report it.