UE 5.8.4 Freezes once the fullscreen button is hit

Hi there! So I’ve tried to launch UE 5.8.4 on my PC. I created a third person project aimed at the desktop. When the editor opened, I was able navigate the viewport and even hit play to run around as the third person character. At this point, the editor was not in fullscreen.

However, once I hit the maximise screen button the editor, it completely froze, becoming uninteractable. And now, whenever I launch the engine, it is just stuck at this window

Does anyone know what might be causing this issue? Any help is much appreciated, thanks!

Hello there @UBETRAYEDTHELAW!

From what you are describing, it sounds like the editor is remembering its window state between sessions. Since it froze while maximizing, the next time you opened it, it tried to restore that maximized window, and froze again at the same point. So the first step is resetting those saved settings, so it opens normally.

To do that, with UE closed, go to C:\Users\YOUR_USER\AppData\Local\UnrealEngine\5.8\Saved\Config, and clear up it’s contents. Then do the same in your project’s folder, should be Saved\Config\ as well. This resets your editor layout and preferences to the defaults, and Unreal will create fresh ones on the next launch.

If the issue persists, I would test by clearing the project’s full cache. Go back to the project’s main folder, and delete folders Intermediate and DerivedDataCache folders. Then re-open UE, so it can rebuild the cache.

If it’s still going, test opening an empty project and maximize the screen from there. If it works as intended, the issue is isolated to your project. If not, I suggest verifying your UE install.