Unreal Engine Issues
Unreal Engine Issues
AreaNavModifiers generated by SplineNavModifierComponent have the component-to-world transform incorrectly applied twice
UE - AI - Navigation - Aug 15, 2025USplineNavModifierComponent was made available in UE 5.4. It generates several FAreaNavModifier instances covering a region with a certain thickness around a USplineComponent, and worked correctly u ...
Available network bandwidth is too low for uncapped but slow frame rates
UE - Networking - Sep 24, 2020The networking system has a max frame rate of 120hz by default. Inside UNetConnection::Tick it computes an estimated bandwidth by using that max frame rate, the engine's max frame rate, and the actu ...
Look at Android GetTimeStamp local file handling
UE - Platform - Mobile - May 29, 2020Only files in UFS or NonUFS manifest that are local are returning a non-minvalue timestamp. While this is expected it is causing issues with logging file handling. See: https://udn.unrealengine.co ...
Changing "Coordinate Light Map Index" When "Generate Lightmap UVs" Is Enabled In A Static Mesh Crashes Engine
Tools - Dec 31, 2019When altering "Coordinate Light Map Index" in a static mesh when "Generate Lightmap UVs" is enabled in LOD 0 the engine will crash or "Coordinate Light Map Index" will be set to 0. A demonstration ...
Crash reimporting a skeletal mesh with less Material IDs than on first import
NOTE: Does not occur in 4.16, entered this to find a fix for licensee to integrate. Error message: Assertion failed: (Index >= 0) & (Index < ArrayNum) [Link Removed] [Line: 633] Array index out o ...
Invalid array length error launching QAGame onto HTML5
UE - Platform - Mobile - Mar 22, 2017Firefox 32-bit Version 52.0.1 This error also occurs in MainRangeError: invalid array length[Learn More] 0943e4e3-83fc-4463-accc-9fd15fd7df6c:157:9 processPackageData blob:http://localhost:53501 ...
Crash when building lighting while in PIE
UE - Graphics Features - Feb 21, 2017NOTE: This issue is similar to (same callstack) as [Link Removed], however this issue is still occurring in 4.15.0. Error Message: Access violation - code c0000005 (first/second chance not availab ...
When using Subversion (SVN) and Lock's comment is Japanese outside SourceControl, parsing of xml fails and Status may become NotControlled.
UE - Foundation - Core - Jun 28, 2019If user lock assets with Japanese comments outside source control, XML acquired in svn status may contain Japanese strings, and XML parsing may fail and become NotControlled. This issue does not oc ...
Wrong WPO motion vectors due to Periodic World Space node
UE - Rendering - Graphics Features - May 13, 2026We've noticed smearing in grass due to wrong motion vectors. This appears to be caused by lack of previous frame support in the periodic world space node. This is how we fixed it: In MaterialTempl ...
iOS fails during build step with OSS Facebook plugin enabled due to spaces in filepath
UE - Platform - Mobile - Feb 8, 2019When a user tries to package or launch onto an iOS device they will fail at the build step due to:[3/8] sh Unzipping: /Users/Shared/Epic Games/UE_4.22/Engine/Source/ThirdParty/Facebook/IOS/FacebookS ...