Q: External hard drive ejects on sleep

Dear BroolynAL,

Well done! You should be congratulated for your hard work finding a solution for this very irritating problem. However, I can't help thinking that a problem such as this, which is affecting so many owners, needs to be addressed by Apple. Its clearly a 'fault' either in the ML software or the way that the USB 3 connection is configured. Really such a fundamental problem should not require industrious and obviously knowledgeable people such as yourself delving into the inner mechanics of what is after all a consumer electronics device. If it was a car, I fancy they would have been required to issue a recall notice by now to fix it.

Dear Bridgwater,

Glad it helped; although I like the professionalism of the Apple Care representatives after two weeks of Mac ownership they were no longer able to help me solve any problem that arose.  Therefore, out of necessity, I made the study of the Apple operating system(s) a hobby.  Still think Snow Leopard is the best Apple operating system released to date.......

This is happening on my wife's iMAC. It is in our bedroom so we put it to sleep at bedtime to keep the monitor from flashing and waking us. Problem is when I click sleep it gives me warnining message about disk ejected improperly and it prevents superduper from performing the scheduled backup at 2:30 AM.

This is a 2009 iMac running snow leopard with a Seagate external drive connected through USB2.

This seems to mean it is not confined to Lacie, USB3, thunderbolt, or Mountain Lion. So, What is left? BTW, no hub involved.

Have used used programs like Onyx or Cache Out X yet? Is this a recent occurrence?  A cache file could be corrupted:

recommend: 1. Repair disk   2. Repair disk permissions  3. if you don't have Onyx or Cache Out X they are really good free programs for Snow leopard ......see download links;  https://www.macupdate.com/app/mac/9538/cache-out-x    and   https://www.macupdate.com/app/mac/11582/onyx   (note go down the page until you see related links and download the one for 10.6).  I would use the automation tab on Onyx and run, though,   you may want to uncheck repair permissions if you have already done that with  Disk Utility.  After the restart I would check everything in Cache Out X program and run it......Hope that helps.

Hello everbody

First of all: sorry for my english, I'm Swiss... I discovered this discussion after having bought a new iMac 27" last saturday. From the beginning, my two external hard drives (LaCie 2Big Quadra and LaCie D2 Quadra), both connected via USB3, have been ejected as soon as my Mac went to sleep. In most of the cases, additionally my Mac re-started after a kernel panic. After a very frustrating visit in the local Apple Store, where they told me nobody has ever heard of this problem before and that it must be a hardware problem, I called Apple Care today - and finally, after 3 hours on the phone, we could solve the problem. So maybe, it helps some of you as well by doing the following:

Start your Mac with safe boot into the safe mode (press and hold shift while pressing the on-button, hold it until a status bar appears under the apple). Try to reproduce the problem. If the problem doesn't occur in the safe mode, it's maybe a problem with the launch agents and the launch daemons (they are deactivated in safe mode) and the following will probably help you: Restart your Mac in the normal mode. In the finder, go to your HD > library > caches. Delete everthing in this folder (not the folder itself), do the same with extensions and compositions. Still in the library, re-name the folder "LaunchAgents" to "LaunchAgents.old", re-name "LaunchDaemons" to "LaunchDaemons.old". Re-start your mac, empty your paperbin and once again try to reproduce the problem. For me, it worked perfect: After this, I didn't had any problems, neither with ejected external discs nor with crashing. I even activated the sleep mode for the external hard disks and tried that one - no more problem. So I hope, the problem could definitly be solved and that it may help some of you as well.

Update: this morning found the drive had disconnected. No error message noting the drive had not been properly disconnected. Turned the drive off then back on and had error message 'drive not recognised by this computer'. Didn't show up in disk utility then when tried to reopen disc utility this application froze and had to force quit.

Decided to shut down the iMac which was taking forever so had to perform hard reboot. When iMac restarted drive mounted and worked correctly.

I will now connect the drive only when working at the computer for backups and unmount and turn off at other times until this is resolved.

Have you updated OS X to 10.8.3? I had this problem with Lacie drives on my new 27" iMac that were daisy chained and connected via the Thunderbolt to Firewire adapter. After updating to OSX 10.8.3 this no longer happens. Drives are left on all the time and never disconnect.

Hi macbirdy

I had the same problem (message for not properly ejeced external drive) with different external HD since the beginning with my MB Air (06-2012), but am no more sure if I had tried before upgrade to 10.8. Not only I had the error message, but also often had fix the partitions (one windows and one mac) and starting over with time machine as the backup was said to be damaged.

After the prodecure that you had described now the problem is gone for me :-)

As test, I have put my the computer to sleep and also shutdown/restarted with the external drive conected and mounted and it was simply mounted again after the computer was back running - without any message or problem.

Cheers and to all and good luck with the solving of problems

I just wanted to add my voice to this discussion. I'm having the same problem where my external USB3 drive is improperly unmounted when my computer goes to sleep (15" Retina MBP, OS X 10.8.4). The drive can't be remounted without restarting the computer. Disk Utility can't even see the drive if I don't restart, no matter how many times I unplug / replug the drive.

The problem happens every time with my USB3 drive, but it also happens (but only occasionally) with my Drobo which is connected using Apples FW800 to Thunderbolt adapter.

I've tried all the software fixes mentioned in this thread (resetting NVRAM, etc...) with no luck. As others have mentioned, I'm also trying the Jettison App, which automatically unmounts drives when the computer sleeps, and remounts the drive when the computer wakes up. So far it appears to be working. It's such a shame that we have to resort to this.

Macbirdy,

Has the problem of disk ejection recurred after the procedure you outlined?  Do the "Launch Agents" and "Launch Daemons" get re-populated after they are relabeled "Old"?

Hi

The problem only recurred two or three times, when waking up the imac by pressing a key on the keyboard instead of pressing the on/off-button. Otherwise, everything works perfect now. The two folders have been repopulated, but don't have the same content.

I was experiencing this problem with an external firewire drive after upgrading to ML.  I installed a little app from the App Store -- Jettison -- for only $1.99 and it seems to fix this issue.  It unmounts the external drive before the computer goes to sleep and automatically remounts it when it wakes up.  I have been running Jettison for the last two days and I have not encountered the error message at all. 

Unfortunately, I may have spoken too soon.  The problem reappeared today, even with Jettison running.

Same here, early iMac 21.5" working perfectly with 10.6 then upgrade to 10.8 and continual problems with  2 x Seagate 3TB Backup Plus drives, now on 10.8.3.

More often that not the drives dont show the power light and / or capacity lights after waking from sleep and when that happens Disk Utility falls flat on its back and cant read the disk and Time Machine goes into meltdown.

Restart the computer and everything works as it should and the gut wrenching feeling in the stomach dissaptes knowing that a few Terabytes of data havn't been lost for good; but I dont want to have to restart my Mac each time.  Eject both volumes before putting the computer to sleep also works, the drives mount correctly on waking from sleep and thats also a pain in the bum but a lesser pain, but after 20 pages on this website and 40,000 views and still no answer to something so fundamentally wrong I'm really ready to throw in the towel with Apple.  Surely they must have an answer by now?

Boy is this getting old.

While I no longer am alerted to the dreaded failed to eject warning, I was wrong to hope the larger problem had gone away. For the third time since this thread began I have had to erase and rebuild my time machine backup. First there is waning that TM failed to backup but the external disk cannot be verified or repaired. This requires erasing and backing up from scratch. I am getting cynical. Perhaps this is Apple's way of saying don't use external drives got TM, only use Time Capsule (for more $$ but for less storage)

Grrrr

Alan