Question Play button in the Animation window does nothing (in play mode or in edit mode)

I encountered a problem that is either a bug or a misconfiguration on my part. The "Play" button in the Animation window stopped working in my main project. See this quick recording:

The animations work normally in the game, and they work when I drag the seek bar to select a particular keyframe, but the Play button itself stopped working.

I copied the same animation controller/clip to a new project, and it works correctly, so the issue is somewhere in my main project. But I can't imagine what setting would affect this. Both projects have the same Time settings. And since the Animation package is built into Unity, I can't remove and reimport it. Both projects are running Unity 2021.3.4.

Any idea if this is legitimately a bug or not?

 

Report a bug via the Help menu.

Given that you can scrub the timeline manually, I can't really see anything else you could do to get the Play button working.

 

Yeah, it's worth a shot I guess. My main project is too big to attach to the bug report, and I couldn't reproduce it in a fresh project, but I'll see if they can figure it out. I might just update to 2021.3.5 and see if it fixes itself.

 

I believe this is a bug. You can see that the drag bar is gone and the marker is gone too.
Then I found that the library folder is *READ ONLY*, close unity application, delete the library folder, reopen the project, and the problem is solved.