I’ve encountered an annoying bug for a while now, dating from Snow Leopard (Mac OS X 10.6) at the least1 where my keyboard stops functioning. The mouse still works, the computer still does whatever it doing, but no key input registers with my Mac. The fix is simple enough, mouse into Activity Monitor, select Dock, quit it, and then the keyboard will work again. I haven’t figured out how to stop it from happening, but at least I can fix it without rebooting – which happened the first few times this happened.
I know that Screen Sharing and Spaces are both involved – the bug doesn’t appear unless I use these tools, in some combination, or in conjunction with some other process. Unplugging the keyboard from the USB port has no effect, plugging a new keyboard in has no effect, not using Screen Sharing and Spaces is not an option, so I live with having to quit Dock once or twice a day…
Footnotes:- maybe earlier, my memory of such things gets fuzzy [↩]