Model A1225 / Early 2009 / 2.66, 2.93, or 3.06 GHz Core 2 Duo processor

172 Questions View all

iMac hangs-up all the time, please help!

Hello from germany!

My iMac 24" from early 2009 hangs up all the time but without an indicated pattern...

What happened when?

Sometimes (1-2x/day) the iMac hangs up when i work with my iMac, sometimes he hangs up when the device is in idle (the mac is on but i do nothing on it). The iMac is becoming very hot on the upper left back. When the failure happens, it seams that the display its repeating to send the last picture (it hangs) an the mac isn't reacting on commands from keyboard or mouse. When i listen to music, then this sound hangs up also. The fans are running all the time. Then the only option is to press the power-button 5 seconds an shut the mac down. After the manually restart the system appears to work fine. I have try to wait when the failure occur - but after seven hours the results are the same: nothing reacts.


  • Processor: 2,93 GHz Intel Core 2 Duo,
  • Graphic: NVIDIA GeForce GT 120 256 MB
  • 8 GB Corsair 1067Mhz DDR3 Ram (2x4 GB)
  • 640 GB HDD


at the moment i have installed OS X 10.8.2 - in the past OS X 10.5.8 and 10.6.8 on the same machine - the symptoms are the same. So i think there is no reason for an software-failure.

The Programs i used every day are: Firefox, Creative Suite CS5 (Photoshop, Indesign, etc.), Aperture, iWork, iLife. But because the system also hangs up when "no" program is open and the system is in idle i wouldn't look for a reason in this programs.

Things i have done in the past to locate the failure:

  • i change the ram-modules -> not the reason, the failure occur again
  • i made a software update from OSX 10.5 to 10.6 -> not the reason, the failure occur again
  • i formatted the hdd an reinstalled the system OSX 10.5 an upgrade it to 10.6/10.8 -> not the reason, the failure occur again
  • i repair permissions with the disk tool from apple -> not the reason, the failure occur again
  • de-/activate the airport / plug/unplug the lan-cable -> not the reason, the failure occur again
  • bring the iMac to an GravisStore - in the tests from this company no failure occur

What can be the reason? Is there an bug on the motherboard/graphic? can the power supply be a reason?

What can i do?



two pictures about the temperatures measured with istat.

1. Bevor do anything:

Block Image

2. After switch to "medium" fan control

Block Image

Answered! View the answer I have this problem too

Is this a good question?

Score 1


The OSX operating system logs events. Look to your system log files to see what is going on, there maybe some hint there. Also run the hardware diagnostics from the OSX install disk. Post any error codes given here. If everything seems good in the log files and hardware diagnostics comes out error free, take out one of the RAM chips and run the system. If the system hangs still shut the system down, move the chip to the other RAM slot and give it a try. If the system doesn't hang, you know you have a bad RAM slot. Please note: This is a comment and not intended to be an answer.


I almost forgot. Download and install iStat. It is a free program that monitors temperatures and such. Click here to read about it and download it. Pay attention to where the temps, fan speed, etc... are when it is running as it should and when it hangs. Please post those here also. Thank you and good luck.


ABCellars - How about moving this all down below as a answer Vs a set of comments which is not what you have here.


Dan, I understand where you are coming from. However, these are probing questions that require a reply from macAfine and not a solution to the problem, thus has not matured enough yet to be an answer.



thanx for your quick support!

I decided to try the way of installing istat and watch the temperatures.

I uploaded two pictures to my article which shows the temperatures & something else.

If you click on the first entry (lüftersteuerung=fancontrol) of the submenu from stat there are two different options: 1. standard and 2. medium. I click on medium...

And then after activate the "medium"-modus, the fans screw to the max and the temperatures sink.


Show 4 more comments

Add a comment

Free shipping on all orders over $100 or containing a Pro Tech Toolkit!

Browse Our Store

1 Answer

Chosen Solution

Your iMac has a thermo cut off circuit so when it gets to hot it will shut down.

You can try using some compressed air to blow out the vent areas hopefully dislodging the dust build up that could be causing your system to over heat.

More likely one of the fans is not working. You can try running an application to monitor your temperature and fan sensors to see which area is suspect Temperature Gauge.

Depending on your skill set you could try replacing the defective fan or bring your system into an Apple Store and have them fix it. Sorry to say there isn't a fan replacement guide. Here's the guide to pull the display unit so you can access the fans iMac EMC 2267 Its also possible you just have a lot to dust build up inside as well.

Was this answer helpful?

Score 0
Add a comment

Add your answer

macAfine will be eternally grateful.
View Statistics:

Past 24 Hours: 1

Past 7 Days: 2

Past 30 Days: 14

All Time: 4,097