GC Crash/UObject hash verify

Development Platform & Builds
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1 
[2026.02.24-13.57.31:039][382]LogSlate: Took 0.003638 seconds to synchronously load lazily loaded font '../../../DominanceTOE/Content/Assets/Fonts/default/DroidSansFallback.ufont' (3848K)
[2026.02.24-13.57.31:183][391]LogStreaming: Display: FlushAsyncLoading(1133): 1 QueuedPackages, 0 AsyncPackages
[2026.02.24-13.57.31:185][391]LogUObjectHash: Error: UObject Hash consistency failure (remove miscount). Checking for memory corruption
[2026.02.24-13.57.31:185][391]LogWindows: Error: appError called: Fatal error: [File:C:\Builds\DominanceBuild\Engine\Source\Runtime\CoreUObject\Private\UObject\UObjectHash.cpp] [Line: 71] 
Unidentified failure for object HorizontalBoxSlot /Engine/Transient.GameEngine_2147482578:B_DominanceGameInstance_C_2147482514.W_CombatTimeline_C_2147469870.WidgetTree_2147469869.HorizontalBox.HorizontalBoxSlot_0, hash itself may be corrupted or buggy.



[2026.02.24-13.57.31:185][391]LogWindows: Windows GetLastError: 操作成功完成。 (0)
[2026.02.24-13.57.31:186][391]LogSentrySdk: flushing session and queue before crashpad handler
[2026.02.24-13.57.31:186][391]LogSentrySdk: Verbose: invoking `on_crash` hook
[2026.02.24-13.57.31:197][391]LogSentrySdk: Error: === Critical error: ===
[2026.02.24-13.57.31:197][391]LogSentrySdk: Error: 
[2026.02.24-13.57.31:197][391]LogSentrySdk: Error: Fatal error: [File:C:\Builds\DominanceBuild\Engine\Source\Runtime\CoreUObject\Private\UObject\UObjectHash.cpp] [Line: 71] 
[2026.02.24-13.57.31:197][391]LogSentrySdk: Error: Unidentified failure for object HorizontalBoxSlot /Engine/Transient.GameEngine_2147482578:B_DominanceGameInstance_C_2147482514.W_CombatTimeline_C_2147469870.WidgetTree_2147469869.HorizontalBox.HorizontalBoxSlot_0, hash itself may be corrupted or buggy.
[2026.02.24-13.57.31:197][391]LogSentrySdk: Error: 
[2026.02.24-13.57.31:197][391]LogSentrySdk: Error: 
[2026.02.24-13.57.31:197][391]LogSentrySdk: Error: Unhandled Exception: 0x00004000
[2026.02.24-13.57.31:197][391]LogSentrySdk: Error: 
[2026.02.24-13.57.31:197][391]LogSentrySdk: Error: [Callstack] 0x00007ff8cdfd3e49 KERNELBASE.dll!UnknownFunction []
[2026.02.24-13.57.31:197][391]LogSentrySdk: Error: [Callstack] 0x00007ff6d190f19b DominanceTOE-Win64-Shipping.exe!UnknownFunction []

The crash happens very rarely and we managed to catch it with some logs.

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2

Hey Daniel,

in almost all cases these kinds of assertions/errors during garbage collection are caused by previous memory corruption of UObjects.

This also means that the callstack and info from when the crash happens is usually not useful, since the memory corruption happened at a previous point in time. You can try running Static Analysis tools on your game or running tests with the “-stompmalloc” parameter to potentially get an idea of any stomps happening.

If you have any gameplay tests that support a long running/looping test scenario that might be a good candidate to leave running for a while to see if you can trigger the memory corruption. Depending on where memory is getting corrupted, it could be tricky to actually get that to happen.

The name of the object from the log might give you a hint, assuming it is coming from the same system, in this case it seems to be a UI widget, so that might be a good place to focus on for a repro.

Kind Regards,

Sebastian

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