Several times today, my Mac (10.6 Snow Leopard) has frozen up. The cursor has become fixed (movable, but the cursor does not change), the screen unresponsive (nothing highlights when I roll over it, I can't interact with any program, or the menu bar). This problem has occurred while working in a number of different applications, Chrome, Thunderbird, Xcode.

I hit alt-cmd + esc to open the force quite dialog, which does work. I've discovered that the system recovers, regardless of which application I close, e.g. I get a freeze when working in Chrome. I bring up Force Close and close Activity Monitor, which has been running in the background for a while. Everything now works again.

My current solution is to keep something non-essential, like Activity Monitor running all the time, so that when the problem does occur I'm not forced to FC something critical (and yes, it still occurs when Activity Monitor is not running). I'm stumped as to what this could be, I only have a few (4-5) applications running at once, the load on the system is minimal. The seems to occur when typing, but as I'm using the keyboard 99% of the time (in Xcode or the terminal) that's not really that helpful.

How can I prevent this annoying lock-up?

  • Which Mac model do you have? Have you already tried the usual things like cold boot and repairing permissions? – guenter Oct 3 '11 at 20:05
  • Cold boot hasn't fixed, what is repairing permissions? I'll be able to check the model tomorrow (it's at work). – fredley Oct 3 '11 at 22:02
  • see this wikipedia entry: en.wikipedia.org/wiki/Repair_permissions. Repairing pernmissions is discussed controversial, but it don't hurts to try it out. – guenter Oct 3 '11 at 22:09
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    OS 10.4 is not Snow Leopard, it's Tiger. Snow Leopard is 10.6. Which one are you actually running? – Matt Oct 6 '11 at 23:11
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    @Ram it's actually sufficient just to open it. – fredley Oct 8 '11 at 18:30

my first suspect with random crashes like you have is bad memory. either by design or by chance, i suspect that a critical part of the OS or an app is getting loaded in to the same memory address, and that segment of memory is bad.

test your RAM!


If you can get a hold of disk warrior it would repair any of your os troubles. I find the disk utility doesn't work that well. You can also try tech too pro it will do the same except all test your hardware so you can see if there's any ram issue or if you have bad sectors sometimes bad sectors cause a problem such as what you explained.

Good luck

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