On Snow Leopard (latest version, but it's been happening for a while), I have the top right corner set to show Spaces, and the bottom right to show the Desktop. Occasionally, often enough to be annoying, and without any reason I can discern, these hot corners stop working. I have tried:

  • changing the action of the hot corners, mouse in (nothing happens), then change back
  • turning off Spaces and turning it back on
  • toggling the Spaces icon in the menu bar (worth a shot, right?)
  • killall Finder
  • killall Dock
  • killall SystemUIServer

None of these work. If I close the MacBook to suspend it, then bring it back up, that fixes the problem, but is less than ideal if I have, e.g. a big download going.

Is there a way to quickly (i.e. not log out/log in, not restart) fix the hot corners? Is there some special program I don't recognize in the System Monitor that will restart the hot corners if killed? Is there something that suspend recycles that I can recycle without suspending?

  • This could very well be related to apple.stackexchange.com/q/33950/10410, but that question doesn't have answers either, and I'm on Snow Leopard, not Lion. I therefore figured it was probably worth making a potential duplicate question.
    – zpletan
    Mar 31 '12 at 16:43
  • Duh, I meant to try sleeping/closing laptop and waking back up. I'll see how that works too, next time it happens.
    – zpletan
    Mar 31 '12 at 18:56

Have you tried restarting SystemUIServer? (killall SystemUIServer) When something like his is happening and restarting the Dock doesn't help, SystemUIServer is the next one to try.

  • +1 This is one of the processes that frequently causes problems and can be killed harmlessly. Mar 31 '12 at 16:52
  • I'd seen the process in System Monitor, but didn't know if killing it would do anything harmful (to my desktop session). If it's harmless, I'll give your answer a shot when it next happens.
    – zpletan
    Mar 31 '12 at 18:55
  • Happened again; didn't work. Bummer.
    – zpletan
    Apr 1 '12 at 2:02

It happened again, and I tried simply closing the MacBook, waiting a couple of seconds, and reopening. Maybe it was a fluke, but it worked. I'll wait and see if it fixes the problem a second time to make sure that it really did something.

This answer is less than ideal, e.g., if I'm in the middle of a big download, so I'd like to wait and see if this answer can help towards a better solution. What does suspend trigger that I could do without suspending?


Can you check in Mission Control if Hot corners are undefined? My Keynote crashed, and a consequence of this was, that the Hot corners have all been undefined in Mission Control.

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