UEFN crashes at 24% "Validating Local Content" with FLargeMemoryReader error

Development Programming & Scripting
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1

I’m having a problem with one specific UEFN project.

Every time I try to launch a session, UEFN starts “Validating Local Content” and consistently crashes at around 24%.

I get this error:

Fatal error: [File:Z:\UEVFS\Root\Engine\Source\Runtime\Core\Private\Serialization\LargeMemoryReader.cpp] [Line: 22]

Tried to initialize an FLargeMemoryReader with a null or empty buffer. Archive name: None.

I also get this warning:

Your project appears to be backed by OneDrive which may cause conflicts or unexpected behavior with other systems.

This only happens with one specific project. Other UEFN projects work correctly.

I also receive the warning:
“Your project appears to be backed by OneDrive which may cause conflicts or unexpected behavior with other systems.”

I have already tried:

  • Validate Project
  • Clearing UEFN cache
2

Hey @VIPALEXSK how are you?

I’ve been trying to replicate this issue but I couldn’t, but I’ll try to help you anyways!

First of all, if you have the project stored in a OneDrive synced folder, pause OneDrive sync and try to open the project again. That should alllow you to work.

If that works, you can follow the steps below to avoid that issue from now on:

Make all files fully available offline:

  1. In File Explorer, navigate to your project folder.
  2. Right-click the folder, then choose Always keep on this device.
  3. Wait for the sync to complete (all files should show a green :check_mark: , not a cloud icon).
  4. Try launching the session again.

Please let me know if this works or if you need more help!