iMac with Mountain Lion freezes

Please make sure that you have no "old stuff" like apps/drivers/tools on board that is not 100% ML-compatible. A way to verify is booting in Safe Mode and seeing if problems persist. If they don't, you want to clean your machine from that old stuff, or upgrade each item to the latest and greatest ML-compatible version.

Maybe your RAM is bad. Test it.

Launch the Console app and see if you find logs, or at least log entries that contain information on what causes the freezes.

I am having the exact same problem, with the exact same symptoms on my late 2009 iMac. I can be working on something, pause for a second and when I attempt to continue I can only move the cursor, nothing else reponds, clicks, keyboard, etc. The machine is still active though, since I can access it on the network. I don't remember exactly when it started, perhaps only sonce the last Mountain Lion update.

I have a similar issue. Looking around here I found there is an issue with the appleeventsd process.

Check on your events log. On mine, it was taking up 97% of processor time. End the process here, or in terminal

"Sudo killall -KILL appleeventsd" seems to solve it, for a while. But the process starts up again before long and you have to keep doing it...

Thanks much for the suggestion. I've started Console and Activity Monitor so I can keep an eye out for anything suspicious. Thus far nothing. I had also found a post about the same symptons related to Safaris. I recently started having a lot of open tabs so I followed that advice as well. It suggested resetting Safari and cleaning the cookies and cache.

I'm having somewhat similar frezes on a 2009 iMac, since I upgraded to Mountain Lion form Snow Leopard. Except I can't move the mouse cusor in my freezes.

I am have a few other issues too. Two of which, a hanging Archive Utility and a broken Spotlight Cmd+Clickfunction, were fixed by force quitting appleeventsd in Activity Monitor.

Its worth noting that it will automatically activate again, but the two issues remained fixed even with appleeventsd running again. I haven't done a reboot yet though.

So perhaps it may fix the freeze issue too?

Before killing appleeventsd, see can you uncompress a zipped or .bzp2 file using Archive Utility. If it hangs you have that issue too.

How much memory do you have (About This Mac under the Apple menu)? Adding more might help since it happens during heavy usage. If your computer is out of warranty, you might check here. This company has certified memory amounts above what Apple considered the limit.

http://macsales.com

I've 8 GB. Sholud be more than ample.

I'm convonced, its crappy coding in Mountain Lion is causing it for me (as those two other issues would imply too)

I agree 8 GB should be enough. I was wondering about the original poster since my 2008 iMac only had 2 GB, which is the minimum recommended. I have read more than one thread where Archive Utility was causing problems and some of the people much smarter than I am typed it was a bug.

Have you tried running the Adobe Flash Uninstaller and seeing if that helps? I tried everything but - fingers crossed - I have not had the issue happen since I uninstalled Flash five days ago. I am curious to know whether I just happened to hit some good luck by coincidence or if removing Flash cured the freezes.

Some background - 2007 imac, froze after lion/mountain lion upgrade, tried everything apple support could throw at me with no results. Programs like Click to Flash did not help.

Never mind. Mountain Lion still crashes using Apple software on supported hardware and even Apple support and the Apple store cannot resolve the problem. Very disappointed that Apple would do something that would make their own hardware unusable. If I wanted to replace a PC frequently I would have bought a cheap Windows box.

On my case this problem have been going on for months, and I am starting to think it does only affect iMacs, as I have found posts on MacBooks freezing but they can't use SSH to access so it is not the same thing. I have found no posts on Minis or Pros showing this problem either. My experience with this problem is long and I am not sure why it is happening, but I can tell you what is NOT making it happen:

- Age of iMac is not an issue. Mine is an i3 3.06 Ghz, mid-2010 and my problems started almost a year ago.

- It is not Memory size or quality. I started with 4 Gb, when I read was memory size, I added another 4 Gb and now have 16 Gb of certified identical modules.

- It is not only Mountain Lion. My problems started when I upgraded to Lion, and after months of frustration I upgraded to Mountain Lion hoping that would solve and see where we are.

I would return to Snow Leopard but I can't. I cannot run the development tools I use on SL. :-(

I tend to think that the problem resides on the event manager, as the mouse is drawn by hardware and that is why it works, which also indicates the graphic card is working. My suspiction comes from the fact that when the problem happens, if I wait long enough doing nothing, the screen dims, so I tried to make the computer sleep by leaving it all night on, but it didn't go to sleep, but the screen blanked. I also logged in using SSH and tried to make it sleep with this command: sudo osascript -e ‘tell application “System Events” to sleep’ but it didn't work. I am now waiting for it to happen to try another one: pmset sleepnow to see if making it sleep takes it out of whatever loop it is in.

Forgot to say that I noticed that the mouse stops sometimes prior to the problem happening. E.g. I am going to click somewhere and the mouse just stops in 'middle air' por a second or two and then keeps going. This tends to be an indicator. When I see this, I stop several apps and it paliates the problem. Actually, by doing this I have avoided it for a while, although I am thinking its not this but pure luck, that the problem is waiting for me to have critical unsaved data before struck me again.