How to diagnose why iMac 2011 internal hard drive won't sleep properly

Question

How to diagnose why iMac 2011 internal hard drive won't sleep properly

Hi guys, hopefully you can help. Whenever I put my 2011 iMac (Yosemite) to Sleep lately the internal hard drive spins down as normal but then keeps spinning up every few seconds. Crucially, the display stays off, but the drive is clearly heard to start up repeatedly.

I've already tried a lot of solutions (there are other similar forum threads that remain unsolved) including resetting the SMC and PRAM, and repairing permissions. Also verifying and repairing the drive through Disk Utility throws up nothing.

I've also created a separate User in case it something I was running causing the issue, and made sure 'Put hard disks to sleep when possible' is checked, 'Wake for network access' is unchecked and there is nothing checked in the Sharing preferences.

So my question is – what else can I do to diagnose the issue? Could it be software related rather than hardware? Thanks in advance!

iMac (27-inch Mid 2011), OS X Yosemite (10.10.4)

Posted on Jul 30, 2015 11:20 AM

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Answer 1

rkaufmann87

Level 10

140,568 points

Jul 30, 2015 11:43 AM in response to get-off-the-bandwagon

Check the Sleep settings and check Wake for Network access.

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Answer 2

Jul 30, 2015 12:17 PM in response to rkaufmann87

Hi, thanks for that. I've tried all variations in the Energy Saver settings and nothing works. The problem started without ever changing those settings so I know it's not that.

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Answer 3

rkaufmann87

Level 10

140,568 points

Jul 30, 2015 12:34 PM in response to get-off-the-bandwagon

You mentioned resetting the SMC and PRAM, sometimes it take 2-3 attempts of each to "take", please follow the directions in iMac SMC and PRAM reset and re-do them. If there is still no change,post an EtreCheck report of your system (Google it) and we can look for obvious issue.

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Answer 4

Linc Davis

Level 10

209,547 points

Jul 30, 2015 12:36 PM in response to get-off-the-bandwagon

Please read this whole message before doing anything.

This procedure is a diagnostic test. It’s unlikely to solve your problem. Don’t be disappointed when you find that nothing has changed after you complete it.

The purpose of the test is to determine whether the problem is caused by third-party software that loads automatically at startup or login, by a peripheral device, by a font conflict, or by corruption of the file system or of certain system caches.

Disconnect all wired peripherals except those needed for the test, and remove all aftermarket expansion cards, if applicable. Start up in safe mode and log in to the account with the problem.

Note: If FileVault is enabled in OS X 10.9 or earlier, or if a firmware password is set, or if the startup volume is a software RAID, you can’t do this. Ask for further instructions.

Safe mode is much slower to start up and run than normal, with limited graphics performance, and some things won’t work at all, including sound output and Wi-Fi on certain models. The next normal startup may also be somewhat slow.

The login screen appears even if you usually login automatically. You must know your login password in order to log in. If you’ve forgotten the password, you will need to reset it before you begin.

Test while in safe mode. Same problem?

After testing, restart as usual (not in safe mode) and verify that you still have the problem. Post the results of the test.

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Answer 5

Jul 30, 2015 1:31 PM in response to Linc Davis

Hi Linc, many thanks for those instructions. Having followed them and booted into Safe Mode, the problem stopped. And indeed on restarting and booting normally the iMac now sleeps properly.

Is it possible that doing this has fixed it?

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