Assertion failed: ParentAnimClass->GetSparseClassDataStruct() [File:D:\build++UE5\Sync\Engine\Source\Editor\AnimGraph\Private\AnimBlueprintCompiler.cpp] [Line: 1268]

In case for those who had this error here is how to solve it download the three files then go:

  1. D:\UE_5.0\Engine\Source\Editor\AnimGraph\Private
    and replace all the files you downloaded
    Debug Error Ue5 - Google Drive

I just checked. These files are the normal 5.0 versions.

I am having the same issue.

Had the same issue, one of the animation blueprints in the hierarchy got corrupted and corrupted all of it’s children.
I suspect that it was created as a duplicate, rather than by right clicking on parent and creating a child blueprint class.

What solved the problem for me was recreating that part of hierarchy.


  • UMyAnimInstance
    • ABP_Base
      • ABP_Player
      • ABP_Enemy (this one was corrupted)
        • ABP_Enemy_A (so that this one couldn’t reach parent’s sparse class data struct)

Tried out re-saving the asset, refreshing all nodes, setting all of the settings to defaults, save - exit - open, no result. Only newly created ABP_Enemy and ABP_Enemy_A fixed the issue.

Hope it helps, and you don’t have too much to copy&paste there :stuck_out_tongue: