Crash / Error when starting Project Assertion failed: Header.Len != 0

Development Platform & Builds
, , ,
1

I worked at a quiet big City Scene in UE5.2 and was importing KitBash Models when out of nowhere Unreal Engine Crashed. Since then I can´t open this Project anymore even if I set the map to start with to a other one in the DefaultEngine.ini file. I also tried opening it with DirectX11 to test if it is a drivers Problem but it still didn´t work. All other Projects of mine can be opened without a Problem.

This is the Crash Report:

Assertion failed: Header.Len != 0 [File:D:\build++UE5\Sync\Engine\Source\Runtime\Core\Private\UObject\UnrealNames.cpp] [Line: 2196]

UnrealEditor_Core
UnrealEditor_Core
UnrealEditor_Core
UnrealEditor_Core
UnrealEditor_AssetRegistry
UnrealEditor_AssetRegistry
UnrealEditor_AssetRegistry
UnrealEditor_AssetRegistry
UnrealEditor_AssetRegistry
UnrealEditor_AssetRegistry
UnrealEditor_AssetRegistry
UnrealEditor_Core
UnrealEditor_Core
UnrealEditor_Core
UnrealEditor_Core
UnrealEditor_Core
UnrealEditor_Core
UnrealEditor_Core
UnrealEditor_Core
kernel32
ntdll

I looked up UnrealNames.cpp and found this at Line 21991-2200 but dont know what it means at all^^:

FORCEINLINE FNameStringView FNameEntry::MakeView(FNameBuffer& OptionalDecodeBuffer) const
{
#if UE_FNAME_OUTLINE_NUMBER
checkf(Header.Len != 0, TEXT(“Cannot make a string view for a name-with-number entry”));
#else // UE_FNAME_OUTLINE_NUMBER
check(Header.Len != 0);
#endif // UE_FNAME_OUTLINE_NUMBER
return IsWide() ? FNameStringView(GetUnterminatedName(OptionalDecodeBuffer.WideName), GetNameLength())
: FNameStringView(GetUnterminatedName(OptionalDecodeBuffer.AnsiName), GetNameLength());
}

Can anyone tell me how to fix my Projecct what this even means?

1 Like
2

I have same issue here, can anyone help?
it happens on 5.31

3

Hey there @CedricO and @ehdrbfb ! Welcome back to the community! This is gonna be a fun one. So let’s start with what we know and work into an assumption.

The error Assertion failed: Header.Len != 0 is failing because it expected the Header that got passed in not to be 0. Since we know Fname is part of an Object’s data, we can assume that it could be literal in that an object is missing a name when queried, or is corrupted. This can also occur if your file paths are far too long (in total), though that has a different error usually attached.

Have you deleted/moved anything from the project outside of the editor?

How long is your largest named asset’s file path?

Are there any completely blank named assets that were imported? (this could be impossible to see from outside of the engine so don’t sweat it if you can’t tell.)

Was this project migrated or built in this version?

1 Like
4

Have you deleted/moved anything from the project outside of the editor? -
Yes,
I lately copy and paste some level from outside because working level didn’t appear in contents browser.
But it won’t work either.
Then I tried to create new level and overwrite it. but it fails I guess
After that my editor crashes like that.

How long is your largest named asset’s file path? - Not too long it’s about 7~8 letters

Are there any completely blank named assets that were imported? - Nope

Was this project migrated or built in this version? -
Yes,
It is moved from 4.28 to 5.0 and last week changed it to 5.31, but at that time, it didn’t crashed. (bit minor errors is showing but still worked)

–

5

For this I’d use the Migration tool in the top left corner of the content browser, just because dragging and dropping things in from other projects can get a bit odd when the content needs to be checked over. Or if it’s missing but it was built in this project, I have fixes for that but we need to get in engine before they will work.

That’s probably just the asset name, but starting from the top of the drive for example:

D:\Gamedev\UE5 Projects\ThirdPerson53\Content\__ExternalObjects__\Work\water\8\I4\NFJNI7E2DR8ZGUZWMPNO09.uasset

If you use world partition or one file per actor without WP, your largest one will usually be in the external objects folder like this.

So we’re down to the less than fun portion of the troubleshooting. First back up your project somewhere safe, maybe twice just to be safe. Once you have, we’re going to go delete and regenerate some files.

Only do this after you have made a backup of your project.

Delete both the Intermediate and Saved folders, then try and open the project.

image

If it fails, revert back to your backup and let me know.

1 Like
6

Hey thank you for the fast reply :slight_smile: I sadly don´t know my longest file paths but I could imagine that while importing models, the import failed and the file was saved with no name or coruppted. Could something like that happen and if yes how can I detect/remove the corrupted asset without beeing able to open the Project? I assume it happened because of KitBahs models because sometimes UE crashes when Importing from Kitbash.

7

I deleted both folders but the error still occurs would it make sense to look for the lastest created files in the Project dictionary and delete them?

8

Interesting. You’re correct though, my last recommendation was just as you described, brute force and deleting the newest assets until you can launch. Though let’s try one more thing first. Could you open your DefaultEngine.ini and change the starter map to something like the built in minimal default or another map with little in it?

[/Script/EngineSettings.GameMapsSettings]
EditorStartupMap=/Game/ThirdPerson/Maps/ThirdPersonMap.ThirdPersonMap
GameDefaultMap=/Game/ThirdPerson/Maps/ThirdPersonMap.ThirdPersonMap
9

thank you I will try that. I already did with a other map of mine but didnt with a starter map yet

10

I changed to the Map and tried it out with and without the “Intermediate” and"Saved" folders deleted but still got the same crash report. Since this Problem occoured I also got UE4 crash reports out of nowhere, but I dont even have UE4 installed.

11

I deleted all Files out of every Project folder which were created on the day of the crash and that fixed it for me. Thank you for the help! :))

2 Likes
12

This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.