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iMac unstable after upgrade to Snow Leopard

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pika2000

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Original poster
Jun 22, 2007
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I upgraded my 2008 iMac to Snow Leopard not too long ago, mainly so I can use iLife 11. However, it seems that my iMac is starting to become unstable. The occurrence is random, sometimes even while I'm doing nothing, but the iMac will lock up (frozen entirely, mouse not movable, sometimes with a spinning beach ball seconds before, sometimes the iMac's screen just turns black) and my secondary display will show a green screen with some vertical lines (this happens all the time when the iMac locks up).

Any ideas? This is getting annoying as I never had this issue on Leopard. I ran the Techtool diagnostic, and everything is shown to be fine.
 
Are using Itunes when this occurs?

My Imac freezes with the same results if itunes is set to automatically download podcasts. I've had to manually manage downloading podcasts one at a time and have not had any freezes since I started doing so (sad that Itunes doesn't work with OSX, but that is what is happening for me).
 
buckawheat said:
Are using Itunes when this occurs?

My Imac freezes with the same results if itunes is set to automatically download podcasts. I've had to manually manage downloading podcasts one at a time and have not had any freezes since I started doing so (sad that Itunes doesn't work with OSX, but that is what is happening for me).
Click to expand...
Hmm, interesting. I don't really pay attention if iTunes is running or downloading podcasts when the lockup occurs.
 
macintoshtoffy said:
All the latest updates? used the 10.6.5 combo update?
Click to expand...
Yup. Thing is, I can have the system up and running for days without issue, even doing intensive tasks like iMovie encoding and RAW image processing, than all of a sudden, it just hard locked while I'm doing nothing or simply browsing the web.
 
I had the same problem with my 2007 i mac and the only way I got my mac back in tune was to do a clean install without snow leopard. So I wasted 30$ with snow but mac is back fast and furious.
good luck with yours. ;)
 
Upgrades to Tiger move it toward leopard problems

4 Gbyte 2008 IMac. Tried to do Christmas calendar. Issues developed and computer crashed. Got it going, but calendar Icon no longer visible, so lost two days work. Messed around and finally computer simply quit. Repair shop found hard drive non-operational and replaced hard drive and upgraded me to Leopard. Seemed to go faster. No calendar icon but after some reading found out Apple had missed this function on first go-around with Leopard and I downloaded upgrade.

Three year old Canon Scanner 9950 F came with Scansoft SE for OCR. Needed to scan a book I had written several years ago and lost the original digital file. OCR worked for a bit, then spinning colored ball and computer refused to shut down even after leaving for one-half hour. Finally pulled plug. Bad idea. Computer would not restart. Back to repair shop. Corrupt system file. Tried OCR again and spinning ball again. Got out and abandoned any attempt at Scansoft SE. I believe Leopard is the culprit.

I think Apple is in a mad rush to make its OS so App friendly they are beginning to disregard the production community that has carried the Mac for so long. I am beginning to find the Mac more finicky than my PC and I like to do things with my computer not be a techie.
 
Just as an update, my iMac is still pretty unstable.

-I installed smcfancontrol and increased the fans' rpm a bit
-The random crash is still occurring. Since they are random (I can go for days without issues, and other times it froze in a short time after rebooting), I can't tell if the instability is getting more or less frequent
-I do notice that now when my iMac froze, my iMac screen no longer turns black, and neither the green lines showed up on my secondary monitor. The screens are intact, everything just froze.

I'm guessing that it might be related to GPU, presumably overheating? Maybe SL is putting a bit more strain on the GPU than Leopard, especially since my iMac GPU is just the Radeon 2600 pro, which doesn't support openCL. I'm turning up smcfancontrol now with both CPU and HDD fan at 2300rpm. Will see how things are going.
 
pika2000 said:
Just as an update, my iMac is still pretty unstable.

I'm guessing that it might be related to GPU, presumably overheating? Maybe SL is putting a bit more strain on the GPU than Leopard, especially since my iMac GPU is just the Radeon 2600 pro, which doesn't support openCL. I'm turning up smcfancontrol now with both CPU and HDD fan at 2300rpm. Will see how things are going.
Click to expand...

I had a 2008 20" iMac (same graphics card) and had random freezes etc. The Apple Store people claimed there was nothing wrong with it, things got worse and it turned out to be a failing (250gb) HDD.

A new HDD later and it runs great with SL (iLife, etc,) used as a recording machine :)
 
pika2000 said:
I upgraded my 2008 iMac to Snow Leopard not too long ago, mainly so I can use iLife 11. However, it seems that my iMac is starting to become unstable. The occurrence is random, sometimes even while I'm doing nothing, but the iMac will lock up (frozen entirely, mouse not movable, sometimes with a spinning beach ball seconds before, sometimes the iMac's screen just turns black) and my secondary display will show a green screen with some vertical lines (this happens all the time when the iMac locks up).

Any ideas? This is getting annoying as I never had this issue on Leopard. I ran the Techtool diagnostic, and everything is shown to be fine.
Click to expand...


1. NEVER(!) upgrade an existing installation. ALWAYS wipe out the entire hard disk and make a fresh installation of the new operating system you want to upgrade to. Yes, that is not only true for Windows, but based upon my own experience this is also especially true for any release of Mac OS X. There is a good chance that those problems are gone once you make a clean installation of Snow Leopard on your system.

2. The current Snow Leopard release 10.6.5 is extraordinarily buggy again. Dashboard, Vienna, ecto and several other applications crash very frequently since the .5 update, while everything ran just fine on 10.6.4. From a stability perspective, 10.6.5 is almost as bad as 10.6.0 was when it was released. I hope that 10.6.6 will address those issues. But if it really will be the minor upgrade that is currently being rumored, I have sincere doubts that it will resolve any issues.
 
I know it won't help your particular issue, but it might help with confidence... I am running 10.6.5 Snow Leopard on my mid-2007 24" iMac with the ATI HD2600pro and have absolutely no stability problems what so ever.

I have been using SL since release and have never had to do anything to the fan speeds to maintain stability when performing day-to-day tasks, using Photoshop CS3 or playing WoW or Osmos.

The only mod I have performed to my iMac since new is to (recently) replace the internal 500Gb HDD with a new OCZ Vertex2 120Gb SSD and I took the opportunity to clean the fans and vents that were accessible while I had the screen out. The CPU fan in particular seemed dusty.

Since the SSD upgrade, I am noting that the fans are running at 1200/1200/700 (CPU/Optical/HDD) even just after a session of WoW.
 
Last edited:
Winni said:
1. NEVER(!) upgrade an existing installation. ALWAYS wipe out the entire hard disk and make a fresh installation of the new operating system you want to upgrade to. Yes, that is not only true for Windows, but based upon my own experience this is also especially true for any release of Mac OS X. There is a good chance that those problems are gone once you make a clean installation of Snow Leopard on your system.
Click to expand...
I did point out that it was a clean install, not an upgrade on top of Leopard. ;)
 
DanielCoffey said:
I took the opportunity to clean the fans and vents that were accessible while I had the screen out. The CPU fan in particular seemed dusty.
Click to expand...
Where are the vents on the iMac? I wonder if I can blow some compressed air through them.
 
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