Disk Drive ejecting itself

My Time Machine disk drive has been "ejecting" itself since I installed Snow Leopard. I'm not unplugging it, or turning it off. I'm not touching it.
I'm getting the following error message:
"The disk was not ejected properly. If possible, always eject a disk before unplugging it or turning it off."

My question is why would a disk drive be "ejecting" itself. I've turned off the auto backups, and unselected the drive as the backup disk. It is still "ejecting" itself which leads me to believe the problem isn't with Time Machine but with something else - something connected with Snow Leopard because this wasn't happening five days ago before I installed SL.

iMac5,1 Intel Core 2 Duo, Mac OS X (10.6)

Posted on Sep 9, 2009 5:40 PM

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961 replies

Mar 25, 2010 3:53 PM in response to judithnewman

I spoke today to some helpful people at Apple, and a senior advisor there is forwarding all the info, including a link to this discussion, to some engineers. Will post what I find out. One thing we did discover is that (at least on my computer) the problem doesn't occur (i.e., the disk doesn't eject itself on wake-up) when I'm running the computer on the battery. As soon as I switch back to the AC adapter, however, it starts happening again. Neither I nor the Apple folks have any idea what this means.

Mar 31, 2010 1:05 AM in response to judithnewman

In the 10.6.3 update I see a fix:
'- improve the reliability of 3rd party USB input devices'
Could it mean improvement? (well, I wouldn't call the external drives input device but maybe the phrasing is not precise or some generic USB thing could have positive side effects, I just hope)
Did anyone with acute problems tried it yet? I wonder if it helps.
Actually I have identical problem only with my only firewire, not with any of the USBs, just have a faint daydream that there is common root mishaps, so fix to this will make me happy too.
I'll try it later.

Mar 31, 2010 7:55 AM in response to raacztomi

just updated to 10.6.3. it seems to work now. test procedure:

1) plugged in both fw HD (externally powered) & USB stick (usb powered)
2) put the mbp to sleep for a while
3) turned it on again
4) accessed both drives & both are working fine (no more "the disk was not ejected properly" notification) & the files are accessible (though on the USB it took a bit longer time)

Apr 1, 2010 3:01 PM in response to judithnewman

FWIW, I thought I'd add my 2 cents to the thread. Been helping my mother with her brand new MacBook. She tried to upload some pics to iPhoto from her Sony Cybershot camera (which worked fine with her iMac running 10.5.8). Camera quickly unmounted and displayed the now familiar error, "The disk was not ejected properly. If possible, always eject a disk before unplugging it or turning it off." I tried setting iPhoto to NOT launch when the camera was plugged in and got the same error in just the Finder. Tried taking the memory card out of the camera and using a USB card reader ... no luck, same problem. Seems like this might be a USB driver issue, which, in this case, was not resolved after updating to 10.6.3.

Apr 2, 2010 5:21 PM in response to judithnewman

I had a hitachi 1TB external hard drive just start self ejecting or just not show up at all a few weeks ago. I assumed it was the hard drive and returned it. Hitachi sent me a 1TB SimpleTech HDD. It showed up for about 30 seconds then self ejected. I moved it to a different usb port, same issue. After trying that a few time, this NEW Mac Mini running 10.6.3, just stopped seeing it completely! This is USB drive issue! My 160GB Seagate works fine and all my other usb devices work fine as well.

Apr 8, 2010 7:18 AM in response to judithnewman

Hi Guys,

I've been following this post for a long time since I had the same problem. I have an external disk for TimeMachine backups. I've been using it every day for 1 year with my iMac 24" with Snow Leopard since it was out. Last month I bought an iMac 27" i5 and from day 1, the disk ejected itself and I couldn't complete a full Time Machine backup.

I tried everything to solve this problem without luck. Last night I changed the USB cable and everything is working as expected. No more ejections problems and I was able to do a full backup to the external drive.

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Disk Drive ejecting itself

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