Unreal Engine 5 Crashes when opening a level (due to nanite) - Help Needed!

Hey UEF,

Had a Unreal Engine 4 project that I upgraded issuelessly to UE-5 EA over a year ago - Just updated the UE-5 EA project to UE-5 Preview with everything working swell until I open a certain level or a older save of that level, in which the engine crashes.
The level(s) works fine on UE-5 EA, however has this issue with this latest update…

Using Windows 11, had the same issue on Windows 10 (doubt this means anything) - Hoping we can find a solution soon.

CallStack:


Assertion failed: ++Iterations < 256 [File:D:\build++UE5\Sync\Engine\Source\Developer\NaniteBuilder\Private\NaniteEncode.cpp] [Line: 962]

UnrealEditor_NaniteBuilder
UnrealEditor_NaniteBuilder
UnrealEditor_NaniteBuilder
UnrealEditor_NaniteBuilder
UnrealEditor_MeshBuilder
UnrealEditor_MeshBuilder
UnrealEditor_MeshBuilder
UnrealEditor_Engine
UnrealEditor_Engine
UnrealEditor_Engine
UnrealEditor_Engine
UnrealEditor_Engine
UnrealEditor_Core
UnrealEditor_Core
UnrealEditor_Core
UnrealEditor_Core
UnrealEditor_Core
UnrealEditor_Core
UnrealEditor_Core
UnrealEditor_Core
UnrealEditor_Core
UnrealEditor_Core
UnrealEditor_Core
UnrealEditor_Core
kernel32
ntdll

1 Like

The assertion fail is happening when iterating through your texture coordinate quantization. I would look at the offending levels in UE5.0EA and check if you might not have some complex objects with complex textures or involved material functions and then try turning Nanite off for those objects. Hope this helps get you on the right path.

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Well it seems I’ve found a Solution -
After looking through nearly all my assets, I found 2 bugged assets that crashed the engine every time I opened/rendered them!
If someone else is having this issue, due the following to find and remove the assets:


I: Launch the engine

II: Open your content browser

III: typed in “static mesh” in the search bar (so all the listed assets are static meshes)

IV: Left Click the 1st asset, then while holding shift Left Click the last asset (so all the assets are highlighted)

V: Right Click one of the highlighted assets (it doesn’t matter which one, this should start loading them) - If everything is going right, this should crash the engine, giving you the same error!

VI: Relaunch the engine and follow steps (II & III) again.

VII: Instead of highlight all the assets and once, start highlight a row/a few at a time, right clicking and seeing if it crashes the engine

VIII: If everything goes to plan, you should short it down to one/a few assets causing the crash - Write down the assets name

IX: Close the engine and open your machine’s file manager

X: Find and Open your project’s files and go to the following: (“Drive’s name”:“Other Stuff may be here”“Your Project Name”\Content) - Open the content folder

XI: Search for the bugged assets name "that we wrote down at step (VIII)

XII: Drag it/them somewhere else (outside of the projects file)

XIII: Launch your engine again and launch your project


If you’re still having the issue, keep looking though all the static meshes as it’s likely more than one of them are causing the same problem (which was true in my case).

Hopefully this helped somebody and excuse my sloppy writing, it’s nearly 2 am for me… - uhdebbie

2 Likes

Glad you found the issue!

Thank you. Was having this issue and it was driving me up the wall. Think I will ensure Build Nanite is unchecked when I import the mesh in the future.