Hot reload causes placed actor to lose variable references

UE - Foundation - Cpp Tools - Hot Reload - Nov 9, 2017

Preforming a hot reload causes placed actors to lose code based variable settings. More repro steps: 1. Open UE4Editor.exe 2. Create a First Person Code project 3. Build the project for Developme ...

Compilation errors with UE_NET_ENABLE_REPLICATIONREADER_LOG enabled

UE - Networking - Iris - Jul 15, 2024

Enabling UE_NET_ENABLE_REPLICATIONREADER_LOG results in the following errors: {{4>[1/5] Compile [x64] ReplicationReader.cpp 4>D:\P4V\UE5-Main\Engine\Source\Runtime\Experimental\Iris\Core\Private\Ir ...

[CrashReport] Assertion on in UMaterialInterface::InitDefaultMaterials()

UE - Graphics Features - Jun 28, 2017

This is a common Mac crash occurring in the 4.16.1 release. I have not found any evidence of it occurring on Windows. The callstack closely matches [Link Removed], which was briefly experienced by ...

Crashes after destroying a skeletal mesh attached via socket name (not bone name), the destroyed mesh remains welded.

UE - Simulation - Physics - Jul 18, 2025

On welding physics bodies during primitive component attachment, UPrimitiveComponent::WeldToImplementation() calls GetRootWelded() and then GetBodyInstance() on the returned root. This searches by b ...

[CrashReport] Crash occurring in Phonon::FPhononReverb::ProcessMixedAudio

UE - Audio - Apr 27, 2017

This is an early trending crash coming out of the 4.16 Preview. Users have not provided any additional information. From Log:/Game/VirtualRealityBP/Maps/UEDPIE_0_StartupMap.StartupMap (0.006787s) ...

[CrashReport] Mac crash - UE4Editor-SlateCore.dylib!FSlateApplicationBase::Get()

UE - Platform - Apple - Oct 5, 2017

This is a slightly common Mac crash that has occurred since 4.17.1. Users have not provided any descriptions of their actions when the crash occurred. Callstack from Log[2017.10.05-15.00.31:683][3 ...

GeneSplicerModule has linking errors in a Development target

MetaHuman - Oct 16, 2025

The FArchiveMemoryStream class is defined in GeneSplicerModule and RigLogicModule. This generate linker error as this doesn't respect the "One Definition Rule"  1>Module.GeneSplicerModule.cpp.ob ...

ResavePackages Commandlet Consistently Crashes in 5.3 In Material PreSave

UE - Rendering Architecture - Materials - Feb 20, 2024

Running the ResavePackages commandlet will consistently result in a crash. The callstack is here: Assertion failed: !IsRooted() [Link Removed] [Line: 265] UnrealEditor_Engine!UMaterialInterface::P ...

In Packaged builds, Chaos Cache Manager can't animate Geometry Collections with Nanite Enabled if Cache Mode is set to Static Pose

UE - Simulation - Physics - Destruction - Feb 27, 2025

In Packaged builds, Chaos Cache Manager (CCM) can't animate Geometry Collections (GC) with Nanite Enabled if Cache Mode is set to Static Pose. The licensee tried to animate a CCM using Sequencer onl ...

Crash on garbage collection - Encountered 20 object(s) breaking GC Clusters assumptions.

UE - Foundation - Core - Aug 15, 2018

Garbage collection crash during opening cinematic. Note after crashing and relaunching the game the saved file appears as 8% complete instead of 0%. Note this crash is also occurring with //UE4/D ...