Unreal Engine Issues

FString.Mid doesn't react appropriately when given negative values for the Count variable

If you use a 5 character string (hello) to call the Mid function and provide 0 for start, -1 for count, it'll give you the entire string. This should either return an assert or treat all negatives a ...

Crash when adding Actor Array Element to a Sequencer Event Struct

Crash when adding Actor Array Element to a Sequencer Event Struct Error message: Assertion failed: 0 [Link Removed] [Line: 56] Source Context: 42 N = FName(*StringName); 43 ...

Crash when changing r.MaterialQualityLevel when FastGeo plugin enabled in cooked build

The engine crashes when the r.MaterialQualityLevel is changed in a cooked game that uses the FastGeo Streaming Plugin. The crash doesn't repro with the same steps in Editor, just in a cooked build. ...

LevelEditor: "Replace Actor" marks level as dirty even when using external actors

When using external actors, adding/removing/replacing/editing an actor instance inside a level does not cause any modification to the Level package, which helps reduce contention for the map file on ...

[CrashReport] UE4Editor_Slate!TAttribute<FText>::Get() [attribute.h:130]

This is a common crash affecting users in 4.16 User DescriptionsI imported an FBX and the editor crashed.alembic import from brekelwhats wrong with the ue4 alembic importer? Source Context 120 ...

Dragging and dropping new materials into Dynamic Material Instance slot results in crash

[CrashReport] UE4Editor_SlateCore!FHittestGrid::GetBubblePath() [hittestgrid.cpp:145]

This is a trending crash coming out of the 4.18 release. Users have not provided any descriptions of their actions when the crash occurred. Based on the affected project names, this crash seems co ...

uexp file of certain maps are always packaged when patching

When generating a patch, (patch pak file) the .uexp file of the Editor Start Map and the Game Default Map are both packaged into the patch, even if another map is specified. Example: Editor Start ...

Orientation Warping breaks incoming poses where bones are in component space

The orientation warping node breaks incoming poses where bones are already in component space. This is because, in EvaluateSkeletalControl_AnyThread, we are repeatedly setting bone transforms direc ...

[CrashReport] Access violation - FLandscapeEditDataInterface::SetAlphaData()

This is a common crash affecting users in 4.15 and 4.16. This callstack was previously linked to [Link Removed], but that had a specific repro case that was fixed in 4.14. Users are not providing ...