4.3.2 freezes when I click Play

I’ve been working on a project for a long time. Unity has started freezing as soon as I click Play.

Rebooting doesn’t help. Reinstalling didn’t fix the problem. I can open Unity and close it again without problems (without trying to Play). Once in a great while it will let me Play, then freeze without me making any changes to the game. When it freezes, it never recovers. I have to End Task to kill it.

How can I track down the problem? I’d like to solve this without wiping the computer, if possible.

Thanks in advance!

EDIT: I created a new project, clicked Play, and it also froze.

I found an answer that worked for me. I had several adb.exe (Android processes) running on my machine. I deleted them, restarted Unity and changed the Build platform to Web Player (was on Android).

You could have an endless loop at the start too

I had this problem on my laptop quite often. I realized recently that this only happens when the laptop was unplugged, so in battery mode.
If you are using Unity on a laptop, try keeping it plugged.