UE crashes whenever I Load Recorded Data into a Level Sequence

Development Cinematics & Media
1

This worked a few days ago, now it doesn’t. I’m in UE 5.6.1. I was able to record mocap from my Vive trackers and view the animation in my Level Sequence. Now whenever I try to import it, UE gives up the ghost. I’ve reinstalled UE, tried it in fresh projects and levels, with various mocap files, with the same outcome. The Nvidia driver is up to date. I get…

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Fatal error: [File:D:\build++UE5\Sync\Engine\Source\Runtime\Core\Private\Containers\ContainerHelpers.cpp] [Line: 8]
Trying to resize TArray to an invalid size of 4294967287

UnrealEditor_Core
UnrealEditor_TakeRecorder
UnrealEditor_TakeRecorder
UnrealEditor_TakeRecorder
UnrealEditor_TakeRecorder
UnrealEditor_Sequencer
UnrealEditor_Sequencer
UnrealEditor_Slate
UnrealEditor_Slate
UnrealEditor_Slate
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UnrealEditor_Slate
UnrealEditor_Slate
UnrealEditor_Slate
UnrealEditor_Slate
UnrealEditor_Slate
UnrealEditor_Slate
UnrealEditor_Slate
UnrealEditor_ApplicationCore
UnrealEditor_ApplicationCore
UnrealEditor_ApplicationCore
UnrealEditor_ApplicationCore
user32
user32
UnrealEditor_ApplicationCore
UnrealEditor
UnrealEditor
UnrealEditor
UnrealEditor
UnrealEditor
UnrealEditor
kernel32
ntdll

thanks

2

Hello there @emarlowe!

The error you are getting refers to an absurdly high number being assigned to the TArray, most likely caused by corrupt or invalida data. So, the first step to fix this issue would be to clear mocap and DDC cache.

In order to do so, close UE, navigate to your project’s directory, and delete the following folders (you can backup them up and move to another location, if you prefer):

<YourProject>\Saved\Takes\
<YourProject>\Saved\Config\TakeRecorder\
<YourProject>\DerivedDataCache
<YourProject>\Intermediate

After that, open a new test project, and record a short mocap, to confirm if the error is gone. If everything is normal, test your main project. Yet, if the issue re-appears there, then part of your project’s core data is affected. At that point, the remaining option would be to export and save the mocap sequences you can, and re-import them into a new project.

3

Thanks for the reply. I did what I could including a full windows restore, but it remains a bug even in a fresh project. The workaround is to simply drag the mocap file into the level sequence and not use the ‘load recorded data’ option. Still get crashes now and then but it’s manageable.