Editor crash when recompiling a blueprint with a key selected in a FRuntimeFloatCurve curve editor

The editor is crashing when recompiling a blueprint that has a FRuntimeFloatCurve curve and a created key in the graph editor was selected during the compile. It seems that the boxes that show the time/value are pulling from a FRichCurve that was null.


  1. Create a new Blueprintable C++ class based on UObject.

  2. Add the property:

    UPROPERTY( EditAnywhere )

    FRuntimeFloatCurve MyCurve;

  3. Create and open a blueprint of that class.

  4. Rightclick in the curve editor for MyCurve and choose add key to None.

  5. Compile the blueprint

  6. Select the key and recompile the blueprint again.

Access violation - code c0000005 (first/second chance not available)

UE4Editor_Engine!FRichCurve::GetKeyTime() [d:\build++ue4+release-4.17+compile\sync\engine\source\runtime\engine\private\curves\richcurve.cpp:373]

I tested this on 4.16.3 and did not experience the crash. But did get the crash on both 4.17.1 and 4.17.2

Hey Crefossus-

Thank you for submitting a bug report. I have reproduced this issue and logged a report for it here Unreal Engine Issues and Bug Tracker (UE-52344) . You can track the report’s status as the issue is reviewed by our development staff. Please be aware that this issue may not be prioritized or fixed soon.