Unreal Engine Issues
Unreal Engine Issues
"Assertion failed: NumberOfFreeBits >= 0" on clients that attempt to connect to a server with the -NoPacketHandler option
UE - Networking - Oct 6, 2020With the rework of IP address resolution in 4.25, this assert now occurs. When no packet handler is used, UPendingNetGame::InitNetDriver calls SendInitialJoin() immediately, before async address res ...
Material slot assignment incorrect after mesh reduction completely removes all triangles from a section
When mesh reduction results in a section becoming empty, the material slots are incorrectly assigned. e.g. if section 0 gets removed due to it having no triangles after reduction, then its material ...
Integer overflow in NaniteBuilder can lead to an editor crash on certain meshes
UE - Graphics Features - Nanite - Jul 10, 2024NaniteBuilder uses an int8 type for ExternalEdges and counts adjacency with a int32. The bug stems for the cast to int8 when adding the adjacency count into the ExternalEdges array. The precision l ...
Moving objects in editor does not update collision
UE - Gameplay - Apr 7, 2015When an object is created procedurally with code and placed into the editor the collision analyzer will detect the object properly. If the object is then moved to another part of the level the coll ...
Indirect lighting cache generates points inside interpenetrating static meshes
UE - Graphics Features - Jun 10, 2015Seems to be an issue with the indirect lighting cache where if you have interpenetrating static meshes (for example static mesh rocks that make up the ground), there are cases where the cache points ...
Blueprint inheritance can cause dangling references to stale UProperties across compiles
UE - Gameplay - Blueprint Compiler - Jun 6, 2017A number of places in the code rely on raw UProperty pointers to track properties they care about. This can present issues when BPs inherit from other BPs, because the parent's class may be Purged / ...
LogAudioMixer warning results in a decrease of performance
UE - Audio - May 21, 2020Unable to reproduce. User believes it is directly related to the speaker they are using when it goes into standby mode. If they unplug the speaker, everything runs okay. After receiving the warning ...
UFE: Can't delete custom launch profiles
UE - Editor - UI Systems - Jul 26, 2023The confirmation message will fails spawning with the following messages in the log: [2023.07.25-20.04.01:038][ 0]LogWindows: Error: Failed to create dialog. The specified resource type cannot be ...
Vector VM - Crash / memory stomp when using > 255 external function calls
UE - Niagara - Aug 12, 2025The Vector VM has only every supported a byte's worth of external function calls, when we blew the limit it would index into the incorrect VM call. The new VM will also overwrite memory when exceed ...
Duplicating / Moving (to another level) an actor with a Hierarchical Instanced Static Mesh component causes a crash
UE - Graphics Features - Nov 14, 2016When you have an actor with a Hierarchical Instanced Static Mesh component that has a Static Mesh set and is populated with at least 1 instance and then duplicate it or move it to another level, it ...