UNetDriver server-side hitch results in ActorInfo->NextUpdateTime far into future

UE - Networking - Feb 16, 2024

A high UWorld::Tick DeltaSeconds (i.e. GameThread hitch) results in a high UNetDriver::TickFlush DeltaSeconds. This DeltaSeconds can high (many seconds) if the hitch is long. This value then affects ...

Crash When Raycasting Against Mesh With Multiple Materials

UE - Simulation - Physics - Feb 26, 2016

When using a raycast trace against a blueprint that has a child component with multiple materials will cause the editor to crash after a few times. This will not be an instant crash, but requires th ...

[CrashReport] UE4Editor_MaterialEditor!FMaterialEditor::GetToolkitName() materialeditor.cpp:820

UE - Rendering Architecture - Materials - Nov 21, 2017

This is a new crash coming out of the 4.18.1 hotfix. There is no record of it previously occurring, so it is possible it may be a regression. Users have not provided any descriptions of their actio ...

Bug in StringTemplate.cpp related to modulo operator in MaterialTemplate.ush (code fix provided)

UE - Rendering Architecture - Materials - Jun 25, 2024

Shader Template files like MaterialTemplate.ush do not submit previous chunks when encountering a `%` character, unless that `%` character is `%s` or `% {...} `. Because the error is happening ...

[CrashReport] UE4Editor_UnrealEd!PackageTools::ReloadPackages() [packagetools.cpp:576]

Tools - Jun 29, 2017

This is a common crash affecting users on 4.16. Users have not provided any descriptions, so additional information is currently unavailable. Source Context 561 ::SortPackagesForReload( ...

Pressing Cancel after ColorPicking a Sequencer's tracked Color will not reverted the color to the previous value

UE - Anim - Sequencer - Jun 22, 2025

Pressing Cancel after ColorPicking a Sequencer's tracked Color will not reverted the color to the previous value. There's a bug when ColorPicking a color that is being tracked in Sequencer - pressin ...

[CrashReport] UE4Editor-TargetDeviceServices.dylib!TRawMessageHandler<FTargetDeviceServicePong, FTargetDeviceProxyManager>::HandleMessage(TSharedRef<IMessageContext,()

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[2017.09.28-15.29.17:473][3 ...

Sequencer frame range progression is not continuous

UE - Anim - Sequencer - Oct 28, 2021

The end of the level visibility section places a DeterminismFence. This causes the issue. The fence clips the frame range and produces a discontinuous frame ranges, e.g. 23201~24000, then 24001~24 ...

Unloading level during PIE leads to editor crash

Tools - Dec 6, 2017

Unloading level during PIE seems to lead to an editor crash. Most easily reproducible by enabling malloc stomp. ...

Gameplay Tags with the string "None" as any of its hierarchical node identifiers behave incorrectly (because of an incomplete generated FGameplayTagContainer::ParentTags array)

UE - Gameplay - Nov 19, 2024

Currently, using the string "None" as a hierarchical node identifier inside a Gameplay Tag (for example "A.B.C.None.D.E.F") is not disallowed by the engine, but results in some incorrect behaviors. ...