Unreal Engine Issues
Unreal Engine Issues
Changing the ComponentClass of a ACharacter twice and trying to set a SkeletalMeshAsset crashes the engine
UE - Anim - Jan 22, 2026Changing the ComponentClass of a ACharacter twice and trying to set a SkeletalMeshAsset crashes the engine with a "Cannot replace existing object of a different class" message. The conditions to re ...
[CrashReport] Access Violation - UModelComponent::GetPhysicsTriMeshData() [modelcomponent.cpp:673]
UE - Simulation - Physics - Oct 2, 2017This is a trending crash coming out of the 4.18 Previews. Users have not provided any descriptions of their actions when the crash occurred. The callstack is similar to [Link Removed], which was ju ...
In a Geometry Collection, enabling Nanite Fallback in a Nanite Enabled collection won't generate a Physics Body when Nanite is disabled
UE - Simulation - Visual - Jun 30, 2025In a Geometry Collection, enabling Nanite Fallback in a Nanite Enabled collection won't generate a Physics Body when Nanite is disabled. To verify this, follow the steps provided in the Steps to Re ...
D3D12 Does Not Correctly Validate Static Uniform Buffers Correctly
UE - Rendering - Architecture - RHI - Feb 12, 2025When adding a Uniform Buffer Struct that has one 4x4 matrix to a mesh pass, validation will fail, due to a Uniform Buffer Struct mismatch. This can be reproduced by adding a mesh pass in project-si ...
Structs cause packaging to fail when Blueprint Nativization Method is set to "Inclusive"
UE - Gameplay - Blueprint - Apr 26, 2017Structs cause packaging to fail when Blueprint Nativization Method is set to "Inclusive" Note: Appears to be a regression (worked in 4.15.1) Error example: UATHelper: Packaging (Windows (64-bit)) ...
GeometryCollectionPhysicsProxy::FieldParameterUpdateCallback() not removing invalid Commands, leading to performance issues
UE - Simulation - Visual - Aug 30, 2025GeometryCollectionPhysicsProxy::FieldParameterUpdateCallback() not removing invalid Commands, leading to performance issues. The licensee has provided their analysis: We seem to have stumbled acro ...
Unreal Insights - GPU Timers don't show on Graph
UE - Foundation - Insights - Oct 27, 2023From Customer: UE 5.3 update broke Unreal Insights adding GPU timers into graph tracks. Debugging the code and cross checking with github/p4v I guess it broke in this revision: Timer graphs no ...
[CrashReport] UE4Editor-Slate.dylib!FMenuStack::PostPush(TSharedPtr<IMenu, (ESPMode)0>, TSharedRef<FMenuBase,()
Tools - Dec 1, 2017This is a longstanding but infrequent Mac crash that has occurred since at least 4.15. Users have not provided any descriptions. Callstack from Log[2017.11.19-04.18.41:283][ 0]LogSlate: Took 0.000 ...
Changing the state of a PrimitiveComponent->BodyInstance while SetSimulatePhysics(false) updates the game thread but does not update the physics behavior
UE - Simulation - Core - Nov 21, 2024Changing the state of a PrimitiveComponent->BodyInstance while SetSimulatePhysics(false) updates the game thread but does not update the physics behavior. In the repro project provided (see addl in ...
Niagara Emitter editor forgets Timeline playback ranges
UE - Niagara - Sep 14, 2020This seems to only affect an emitter and not a system asset. ...