Unreal Engine Issues

Calling FHttpResponsePtr::GetContentLength() from OnRequestProgress delegate returns different values on Mac/iOS than Windows

Licensee was looking for a way to get total file size to display download progress. On Windows (which uses the curl library for Http request/response), binding a function to the OnRequestProgress d ...

For a TMap with C++ enum keys, deleting and re-adding a map entry in the Editor can corrupt the map data.

When adding an entry to a TMap using UE's property editors, in most cases the new entry comes with a default-initialized key (if such key already exists, the insertion fails). The case of a UENUM de ...

Crash (Assertion failed "SystemInstanceController->IsSolo()") when enabling "Start with Tick Enabled" on a Niagara Component

Currently, Niagara Components are only expected to have their TickComponent() method called when their system is marked as "Solo", which makes them be simulated individually. In the most common scen ...

Crash when resizing window using Quad Stereo Buffer

We noticed crashes in our application when we attempted to resize a window or switch to full-screen mode. Hence, resizing windows and switching to full screen will result in a crash on Unreal Engine ...

Sequence with restore state set is causing a "Fatal world leaks detected" crash

We recently had a few occurrences of crashes caused by a "Fatal world leaks detected" error when unloading a level (in a packaged game and in editor). I tracked down what was keeping a references t ...

[CrashReport] UE4Editor_Engine!UModelComponent::CommitSurfaces() [modelcomponent.cpp:163]

This is a somewhat common crash that has existed since at least 4.14.. It appears related to an Undo operation on geometry. User DescriptionsUndoing a move of a boxbrush wall and staircaseundoing i ...

LastEditedDocuments is grow-only and will accumulate null entries as graphs are created and destroyed

Virtual Joystick + Swipe to Look = Choppy camera movement on newer iOS devices

User Submitted Video: [Link Removed] User Description: "Swipe to look (with only the left virtual gamepad joystick) is undoubtedly the established gold standard for 3D First Person mobile games. ...

[CrashReport] Fatal error: Couldn't find shader - FMaterial::GetShader()

This is a common crash affecting users in 4.16. User DescriptionsTried to edit the VivePreController Meshtried to edit SM_Skysphere after shaders had finished compiling. For no other reason than th ...

NavLink Proxy CHILD ACTOR stops working in a Packaged and Standalone game

NavLink Proxy CHILD ACTOR stops working in a Packaged and Standalone game. Works as expected in PIE. Licensee Description: Force Rebuild on Load is not called and the nav links as child actors do ...