iMac freezes

Stop using Onyx.

But more importantly find out if the RAM has gone bad, or your disk is too full*:

http://www.macmaps.com/badram.html
http://www.macmaps.com/diskfull.html

- * Links to my pages may give me compensation.

Out of curiosity why do you advise against using OnYx?

Thanks in advance,

Roger

If used at the wrong time, it can make it impossible to launch any applications.

So are you saying in general don't use it or were you making the statement for the OP's current problem?

i'm noticing this identical behaviour on my 27 inch core i7 imac. I've used the built-in diagnostic tools and it reported that all is well. I've checked my disks using Disk Utility and all is well.

I've even had the lock up occur while booted from the install DVD, so that tells me that it isn't anything related to my OS installation or setup.

And like you, it seems to only happen during idle moments. It hasn't yet happened while I'm actively doing something on the machine. That could be a coincidence though, i'm not sure.

I just phoned Apple support and they said I have to take it to a tech centre for further diagnostics. Hopefully they are able to get to the bottom of this problem.

Both. The only time to use it is if you know what you are doing, and have a backed up system are willing to risk it failing more than helping.

Got it, thank you!

Ghozer,
question for you: does the locking up occur while you are working on the computer? Or only when you've left it for a bit?

it seems we're not alone with this sort of issue. There are similar postings at the following thread:

http://discussions.apple.com/message.jspa?messageID=11631251#11631251

so far my lock ups have only occurred when the computer is idle, never when I'm working on it. So if I leave the computer and it only has one or two things running (eg say a web browser and chat window) then most likely when I come back it will be frozen.

If, however, I run many apps, like apache, and mysql, and rails, and leave those running, then it makes it through the night and is still running just fine when I come back in the morning.

I was hoping that it might be related to the energy saver setting 'Put the hard disk(s) to sleep when possible', but I turned that off earlier tonight and I experience a lockup since then.

I have two USB 2.0 external disks and a USB 2.0 flash drive plugged in. I will try unplugging those and see if the computer still locks up.

Oh, and yesterday, I did get a lockup after having run Disk Utility by booting off of the install disk. Disk Utility reported all was well...then i just left the computer for a few minutes and came back and it was locked. So that tells me that my problems isn't a software conflict or anything like that on my install of Snow Leopard. But it could be a firmware issue or an issue with Snow Leopard.

Anyone have any theories?

I spoke to Apple yesterday and the only thing they were able to suggest was to take it for service. I'm not convinced that its an isolated issue with my computer though.

Same thing happening to my one-week-old 27" i5. In my case it freezes and I get a little round multicolored ball as a mouse pointer and the only way to go is to push the button and turn it off.

It happened 4 times so far this evening. I also have two external hard disks, but I cannot afford not to have them, all my photos are there!

My computer freezes when I run lightroom and photoshop, or lightroom and safari at the same time.

Sergio,

Stop turning off your machine that way! I believe what is occurring is you are simply running out of memory. Run Activity monitor and see where you memory is being used. Photoshop, Lightroom and Safari all use a lot of memory and if you use them all at the same time you will get to a point where your machine run's out of available RAM and has to do memory swapping. Memory swapping is very slow and would explain your spinning beach ball. I suspect if you upgrade the RAM in your machine that will take care of your problem.

You are doing more damage than good by force shutting it down so please stop it before your damage your OS.

Regards,

Roger

Frank and Sergio,
Please start a new topic thread here:

http://discussions.apple.com/forum.jspa?forumID=1110&start=0

You'll get a wider audience and won't confuse Ghozer with solutions that don't apply to them. Similar issues, don't necessarily mean similar cause. Especially if the solutions offered here fix Gozer's problem, and they don't fix yours.

my issue does not involve the beach ball. It locks up completely and does not recover. The screen just stays frozen, no motion at all from anything, no reponse from mouse/keyboard. And the machine does not respond to pings. I have to hold down the power button for 5 seconds to cause it to shut down.

I've tried unplugging all peripherals (except for my 2nd monitor) and it still exhibits the lockup. I will try to unplug my 2nd monitor shortly and see if that makes any difference (I doubt it will).

Here's a recap of what I do know:

- the lockups have, thus far, occurred while the system is idle (ie when i'm not using the machine)
- sometimes it happens before the screen goes to sleep and that leaves me viewing whatever was on the screen at the time the lockup occurred. So the video card is still delivering a signal even though things are locked up, but the mouse cannot be moved, the keyboard does not respond. I did try using a USB keyboard & mouse as well to see if the problem is somehow related to the wireless keyboard/mouse that came with the iMac but it made no difference.

- when the machine freezes up I still hear the fan running inside the machine and the machine is still very hot (as usual).
- I have had this occur even when I've booted from the install DVD, so i think that rules out the possibility that its something specific that I've installed.
- I have tried running the machine without any USB devices or FW devices and it still exhibits the lockup.
- I spoke to Apple and they have looked at my system logs and were not able to determine what the issue is and they advised that I take it to an authorized apple dealer for diagnostics.
- I have run the extended Apple Hardware Test (AHT) three times and no problems were found.
- I have run disk utility on all drives, and no problems found.



Theories:
- it could be the CPU itself locking up.
- it could be a bug in Snow Leopard itself.
- it could be some other strange hardware glitch with my system.

I'm debating now whether to take it to a local apple dealer. They would have to keep my system for at least 4 days, but I"m guessing it would be longer. I'm basically trying to determine whether the problem is a bug specific to my system or whether its something that apple might fix in a future update.

Any suggestions as to what else I could investigate to try and further understand this problem?