Weird bug: entire editor UI started disappearing in Play mode, in any 5.x release, in any project.

• OS: Windows 8.1 (64 bit)
• GPU: GTX 680

This started today, out of the blue. I used 5.4b22 and 5.3.5p4 when this happened. Checked on about a dozen of editor releases down to 5.1 and on half a dozen of projects, including empty ones, and this issue is exactly the same everywhere. The only editor versions where this doesn't happen are 4.x ones, like 4.6.8.

To add to this, some elements are missing outside of play mode, in particular all move/rotate/scale tool visualization (arrows, circles and so on) and perspective selection tool in the top right corner - as far as I see, everything drawn by editor class called Handles is dead:



Also, UI seems to be actually present and working, it's only the rendering that fails, as far as I see. You can still hit the field editors in Inspector, select objects in Hierarchy and so on. Color fields are a curious partial exception to the bug - if you manage to hit them in that gray emptiness by chance, tiny color preview rectangle will reappear where it should be, and will show the proper color (you can see that on the first image).

What I've tried so far:

• Creating a new project - No effect
• Removing all Unity folders in AppData/Local, AppData/LocalLow and AppData/Roaming - No effect
  
• Installing new version of Unity (5.3.5p5) - No effect
• Installing new NVIDIA GPU driver (went from 361.x to 368.x) - No effect
• Disabling all applications with overlays (Steam, GOG, NVIDIA Shadowplay) - No effect
• Restarting the PC (who knows, right) - No effect

There are no errors anywhere in the Editor.log, unfortunately. Can anyone help me?

 

Solved it.

Removing all registry keys in HKEY_CURRENT_USER\Software\Unity Technologies and HKEY_CURRENT_USER\Software\Unity, restarting the PC and relaunch the Editor has helped me. As far as I can guess, Unity 5.4b22 is the culprit and somehow corrupted important registry keys used by Editor UI.