I need help! I’ve been working on this project for a few months (although there are elements of earlier projects) – there are some gameplay systems but I’ve been mostly concentrating on getting a world partition-enabled level set up that looks good and runs at least ok. I had a harddrive error maybe a week ago, but everything was working fine except for a few files. After working all night last night, and shutting down the editor without a problem, it all of the sudden has started crashing on launch.
Last night I was doing asset management. I created a few new materials, modified the default materials on a few static meshes, placed some assets in a staging/overview level, and added a number of assets to collections. I believe that’s it. Everything on my computer has been updated as of this morning. The project is fairly massive, and ironically I was trying to cut out unneeded assets, but again, it opened fine just last night.
So, how do I deal with this? If there is a particular corrupted file, how do I find it? If it’s my harddrive, could I potentially move the project to a different harddrive and try to open it, or is that dangerous? How can I avoid this in the future?
Can anyone tell me more about script serialization and deserialization?
Here’s the full error message:
Assertion failed: Export.ScriptSerializationStartOffset == (Tell() - Export.SerialOffset) [File:D:\build++UE5\Sync\Engine\Source\Runtime\CoreUObject\Private\UObject\LinkerLoad.cpp] [Line: 6295] Serialized script property start offset does not match offset during deserialization
UnrealEditor_CoreUObject
UnrealEditor_CoreUObject
UnrealEditor_CoreUObject
UnrealEditor_Engine
UnrealEditor_Engine
UnrealEditor_InterchangeEngine
UnrealEditor_CoreUObject
UnrealEditor_CoreUObject
UnrealEditor_CoreUObject
UnrealEditor_CoreUObject
UnrealEditor_CoreUObject
UnrealEditor_CoreUObject
UnrealEditor_UnrealEd
UnrealEditor_UnrealEd
UnrealEditor_UnrealEd
UnrealEditor_Core
UnrealEditor_Engine
UnrealEditor_UnrealEd
UnrealEditor_UnrealEd
UnrealEditor_UnrealEd
UnrealEditor_UnrealEd
UnrealEditor_UnrealEd
UnrealEditor
UnrealEditor
UnrealEditor
UnrealEditor
UnrealEditor
kernel32
ntdll
…
Any help would be much appreciated!
Hey @Sleazy_Mudkip!
Try running a verification scan on your installation of UE!
Pretty sure this is engine files, not project files. 
Hope that helps!
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By verification scan, do you mean through command line?
I’m running chkdsk right now and it’s found a few things in my project already. (Looks like it’s gonna take 3 hours though)
thanks!
Chkdsk is also a good idea!
I meant this though:
Thanks, I forgot that was there. I canceled the chkdsk to see if it would work, but no luck. I’ll have to start it running again but it was worth a shot. I also tried deleting the derived data cache (I’d already deleted the saved and intermediate folders except for Collections.)
Worth noting that other projects boot up fine. I’m so frustrated with myself for not backing up the project for months. Fingers crossed I can fix it
quick update…
chkdsk finished, and I was able to “analyze” and “optimize” in the disk manager, which wasn’t working before, bringing my d-drive from an unknown % fragmented to 5% to nothing. Probably a good habit to get into, but it wasn’t the solution.
I will say it’s not your hard drive, so no worries there. I don’t even think that opening the C++ file will help because you don’t know WHAT it looks like after “Deserialization.”
It might be a wash, where you’re able to keep some creative products from it, hopefully. Last ditch effort, I’d go to that file in Windows Explorer, back that file up, open the LinkerLoad AND the LinkerLoad from another project, and copy that line from the working project to the dead one maybe?
Yeah, a hard drive issue would be even worse at the moment. Everything seems to be contained within the project though. I’ll look more into Linker Load, this is the first time it’s been relevant to my work. Very much appreciate all the advice
I opened the log in /saved and it looks like the editor is finding a crap-ton of “malformed tags” right at the end. Guess I’ll go through and delete them all manually before I throw in the towel.
That sounds REALLY promising. Because of the nature of the issue, if there are malformed tags that makes me think they’re getting tossed out before conversion but they’re still expected… making what’s expected vs what’s received different. Hence the “Property start offset” difference? I’m not sure, just an educated guess.
Great news! I’ve got things back up and running with only a few missing assets in my game world.
There was a large number of External Actors with corrupted tags, and I noticed a few files contained unexpected second external actors. But a couple of messages stood out:
[2025.04.16-15.57.58:442][ 0]LogAssetRegistry: Display: Asset registry cache written as 331.2 MiB to D:/Unreal Projects/WaywardBayBlues/Intermediate/CachedAssetRegistry_*.bin
[2025.04.16-16.00.12:062][ 0]LogAssetRegistry: Warning: Cannot read AssetRegistry Data in D:/Unreal Projects/WaywardBayBlues/Content/NorthernIsle/LandscapeMaterial/LandscapeTextures/T_DetailCliff.uasset, skipping it. Error: EReadPackageDataMainErrorCode::InvalidObjectCount.
and then another right before the thing really went haywire:
[2025.04.16-16.34.35:099][ 0]LogFileManager: Error: Requested read of 1019975860 bytes when 39802017 bytes remain (file=D:/Unreal Projects/WaywardBayBlues/Content/NorthernIsle/LandscapeMaterial/LandscapeTextures/T_DetailCliff.uasset, size=39815567)
[2025.04.16-16.34.36:209][ 0]LogOutputDevice: Warning:
There seemed to be no order or reason to the corrupted files. Maybe there’s a lesson in there somewhere lol.
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