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
  • 1
    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.

| improve this answer | |
  • 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.

| improve this answer | |

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.

| improve this answer | |

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .