iMac startup gets stuck on grey screen

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iMac startup gets stuck on grey screen

This is an intermittent issue and has only been happening for the last week or so. When I start up my iMac (bought early 2008, running Snow Leopard and fully updated) it will get stuck on the grey screen before the apple logo appears.

I have to hold the power button for a few seconds to shut everything down completely and turn it back on. Second time round it seems to power up fine (so far) so I'm a bit bemused as to what the issue is. I keep my external HD plugged in, so that's always connected when I boot up, but that hasn't been an issue before...

I've been having the issue since I bought my iMac back to uni. I'm always careful to package it properly (back in its original box) but I guess maybe it got clunked in the car? I don't know whether that would have an impact or not. I'm also careful to keep around 100Gb free on my HD to keep it running smoothly.

Any ideas would be hugely appreciated, as final year of uni is not a great time for my Mac to break!

20-inch iMac (2008), Mac OS X (10.6.6)

Posted on Jan 13, 2011 7:16 AM

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Answer 1

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rkaufmann87

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Jan 13, 2011 7:53 AM in response to natbradbury

I think you have enough HD space but I'm not totally positive, how big is the total disk? 100GB sounds like a lot however if you have a 1TB drive it's not enough!

Also can you tell us what troubleshooting you have already tried so we have a starting point?

Roger

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Answer 2

natbradbury Author

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Jan 13, 2011 8:24 AM in response to rkaufmann87

My HD is 320GB, so I presumed 100GB was surely enough. I have moved the plug from an extension lead to being plugged directly into the mains and have restarted twice and both restarts have been fine - but like I said the problem hasn't occurred every time I turn my iMac on, so I'll just see how it goes and get back on here if the problem persists 🙂

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Answer 3

rkaufmann87

Level 10

140,478 points

Jan 13, 2011 8:32 AM in response to natbradbury

OK, yes 100GB out of 320GB is plenty of space, the rule of thumb on Macs is you should have 10-15% of HD space available.

Regarding your power, that's a possible cause. If it does prove to be the problem I would recommend investing in a battery backup to ensure your iMac is not only is getting consistent power but is protected in the event of power failures or power spikes.

There are some things you can check, although they aren't 100% definitive they can give some clues. First is open Disk Utility (Applications-Utilities-Disk Utility) and check the S.M.A.R.T. status of your internal HD. It should say Verified, if it doesn't it's definitely in trouble and either needs repairing or replacing. You can also run Repair Disk Permissions in Disk Utility. Both actions should take less than 10 minutes on your machine.

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Answer 4

natbradbury Author

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Jan 13, 2011 2:26 PM in response to rkaufmann87

Hmm, neither changing the power from the extension lead to direct to the mains nor running those tests in the Disk Utility seems to have helped (though the Disk Utility checks didn't come back with any issues).

Restarting doesn't appear to be the issue, I seem to get stuck on the grey screen only when I'm turning my iMac on.

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Answer 5

rkaufmann87

Level 10

140,478 points

Jan 13, 2011 4:03 PM in response to natbradbury

One very simple thing to do is go to System Preferences - Startup Disk and if your internal HD isn't highlighted then click on it. It's possible your system has "forgotten" where it's startup volume is located.

If it's already highlighted then you can run Apple Hardware Test to see if your machine has any hardware problems. It's not a definitive test but if it does detect some errors then you have a clue. Here are the instructions:

http://support.apple.com/kb/ht1509

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Answer 6

Tom K 7

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10 points

Mar 14, 2011 7:13 PM in response to rkaufmann87

Hi rkaufmann87,

I had this 30sec lag grey screen prior to start up on my new early 2011 MBP, I had cloned the system drive soon after loading my extra programs, i did boot from an external back up drive to do this.
as you pointed out, re-checking my "start-up drive" in Sys Prefs did the trick.

thanks for that. Your a legend, I see by your many posts you maybe in the "Guru" league.
PS, i run it in 64 bit, all runs very well, and extreemly Fast. during encodes it blows away my early 08 Macpro 3ghz Quad core...

Thanks again
Tom K7

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