Mum's Mid 2007 iMac suddenly became extremely slow a few days ago. It takes over an hour to boot, and once booted it beachballs almost constantly in every app. Clicking an icon on the desktop takes a minute or so to respond.

It didn't gradually get slow, she must turned it on one day and it was like that.

I have replaced the hard drive with one that has no data yet. I booted off a firewire 800 drive with an OS X installation that boots up perfectly and is fast with another mac, but on this mac it is just as slow as the drive I assumed was failing and removed.

Booting from a mountain lion recovery partition is similarly slow (I never actually waited for it to boot, but it was taking way too long at the grey apple logo when I gave up).

What could cause this?

  • 2
    Just a supposition : A CPU running on secure mode because it's overheating – Matthieu Riegler Apr 17 '13 at 12:30
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    I agree with Matt. I once took my mini apart and didn't connect the fan properly. The system ran like molasses. OS X will throttle the chip if there is a fault in the fan to avoid overheating. If it can't keep the temps down that way, it'll shutdown. But check towel sure your fans are working or there isn't a fault with your heatsink. – user10355 Apr 17 '13 at 21:21
  • If there was a heat issue, wouldn't the fan be screaming? It's not. How can I check the temperature? Perhaps from single user mode, as that is the only thing tha works reliably. One time it was still booting after 18 hours. – Abhi Beckert Apr 27 '13 at 20:39
  • Not if the heat issue was due to a dead or obstructed fan. – JRobert May 24 '13 at 0:58
  • did you check your hdd? – dennismuijs Apr 29 '14 at 8:43

Check the RAM.

Ordinarily bad or improperly seated Ram will prevent booting BUT it is worth checking.

However, this sounds like a hardware problem as you have done so much troubleshooting.

My suggestion is to bite the bullet and take the old Mac into a brick and mortar Apple Store.

  • I tried reseating the chips. They're a different type to others I have around so I can't replace them. I guess I could try just plugging one in at a time... closest authorised Apple repair ahop has a $150 diagnosis fee :-( – Abhi Beckert Apr 17 '13 at 18:43
  • If the RAM is faulty or not seated properly, the system won't boot and you'll know because it'll kick off a distinctive set of beeps. – user10355 Apr 17 '13 at 21:17
  • Booting off either of the two RAM chips didn't help. – Abhi Beckert Apr 27 '13 at 20:32

Have you run the Apple Hardware Test? Hold down 'D' while the Mac boots up and it'll run through some diagnostics - see the link for more details.

It's quite likely this will identify the issue but I'm pretty sure a trip to an Apple Store or authorised repair place will be likely.


If you have more than ten or so files or folders on your Desktop, move them, temporarily at least, somewhere else in your home folder.

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