Unreal Engine 5 crashes on Start up

Error Message:

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Assertion failed: NumBytes == Strings.Num() [File:D:/build/++UE5/Sync/Engine/Source/Runtime/Core/Private/UObject/UnrealNames.cpp] [Line: 3357] UnrealEditor_Core!LoadSeparatedNameBatchInShardOrder() [D:\build++UE5\Sync\Engine\Source\Runtime\Core\Private\UObject\UnrealNames.cpp:3357] UnrealEditor_Core!FNameBatchLoader::Load() [D:\build++UE5\Sync\Engine\Source\Runtime\Core\Private\UObject\UnrealNames.cpp:3493] UnrealEditor_Core!LoadNameBatch() [D:\build++UE5\Sync\Engine\Source\Runtime\Core\Private\UObject\UnrealNames.cpp:3502] UnrealEditor_AssetRegistry!FAssetRegistryReader::FAssetRegistryReader() [D:\build++UE5\Sync\Engine\Source\Runtime\AssetRegistry\Private\AssetRegistryArchive.cpp:140] UnrealEditor_AssetRegistry!FAssetDataGatherer::Run() [D:\build++UE5\Sync\Engine\Source\Runtime\AssetRegistry\Private\AssetDataGatherer.cpp:525] UnrealEditor_Core!FRunnableThreadWin::Run() [D:\build++UE5\Sync\Engine\Source\Runtime\Core\Private\Windows\WindowsRunnableThread.cpp:146]

AMD Ryzen 5 2600X
Radeon RX 580
16 GB of DDR4 Ram

It was running fine for the past few days, but yesterday it just decided to start crashing when I first start it. I tried reinstalling it before to see if it would fix it, but it just gave me the same error.
Any Ideas on how to fix it?


Hi, I have the exact similar issue as Justin here. May I know if there is a solution? Now I could not open my levels done in Unreal 5 anymore, this is quite serious. Hope there is some help.

I tried uninstalling, reinstalling unreal5, uninstalling, reinstalling to another folder and deleted all memory temporary files on windows, and it still doesn’t work. I don’t understand why a simple reinstallation cannot fix this “back to default” for unreal engine 5. Why is the realy problem here?

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I still could not figure out the issue. I been looking for a solution forever, and I still can’t find anything sadly.

Did you manage to fix it?
Getting the same error here. Can’t open my project anymore…

Hi guys, for me worked to delete the folder:

Hope it helps.

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I was suffering from this up until recently, this is how I solved it…

This error comes from a corrupted CachedAssetRegistry.bin file. Reinstalling it does not fix the file.

To fix this, you are going to want to go to file location C:\Users\username\AppData\Local\UnrealEngine\5.0\Intermediate - Locate the file named CachedAssetRegistry.bin and delete it. After deleting it, you should be able to launch


Thank you very much, my problem is solved :slight_smile:

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definetly the fix. THANKS!

This works also for others on 4.26 or 4.27 which i tested… So if some one googles and search for this ERROR: /Engine/Source/Runtime/AssetRegistry/Private/PathTree.cpp]

there is an awesome amazing side effect that has happened twice for me! :smiley: ALL OF MY BLUEPRINTS GOT DELETED