Q: Mountain Lion improperly ejects external disks

We have 3 laptops here - 2012 Macbook Pro, 2010 Macbook, 2008 Macbook. All are running on 10.8.3.  This issue  shows up  frequently (but not every day) on the Macbook Pro. It seldom shows up on either of the Macbooks.

Has anyone else tried reformatting their hard drive and then reinstalling Mtn Lion? This is what Orenn said worked (on 4/9/13)... "Lots of problems since i upgrade from Lion to ML, so i reinstalled ML, and it did not solved anything, but after i format my mac and installed a fresh copy of ML, everything works smooth and no ejection issues."

After about a week of using the Glyph with my Macbook and experiencing no problems, I  re-hooked it to the iMac and the same old problems resumed almost immediately.

I called Apple Support and this time I got a technician who seemed to cut through all of the confusion like a hot knife through butter (and I told her so). Let’s hope her approach works in the long term. It sure works now. She told me the problem was related to my iMac’s sleep settings and instructed me as follows (with the external h.d. disconnected):

Click on Black Apple in top left corner. Choose System Preferences. Go to second row of symbols, click on Energy Saver Take both sliders to NEVER. Ignore the warning with OK. Uncheck "Put Hard Disk To Sleep When Possible." Uncheck "Allow Power Button To Put Computer To Sleep." Close System Preferences with Red Dot. Also, try to Quit all programs (not with red dot) but with Command Q or by clicking on the name of each program you are in (beside Black Apple) and choosing Quit.

I then connected the external h.d. and all worked well. I then ejected it, disconnected again, re-connected again, and all was well. Time will tell if this works with normal daily procedures. But it seems like a breakthrough.

She also gave me a link to “our best video tutorial shorts if you ever need them”: http://support.apple.com/videos/#macosandsoftware

ernest255,

Did the Apple rep advise you to leave your Energy Saver set at NEVER forever?  That makes no sense to me.  I could see extending the setting so the computer times out after a longer period (like 1 or 2 hours), but not forever. And, why uncheck "Allow Power Button To Put Computer To Sleep"?  This entire set of instructions seems a bit mysterious. 

From now on I will manually control the sleep function as needed.

Send Apple feedback. They won't answer, but at least will know there is a problem. If enough people send feedback, it may get the problem solved sooner.

Feedback

So, Ernest... please clarify... are you saying you are now leaving your Energy Settings for your computer AND your screen on "Never"? And are you also leaving the "Put Hard Disk To Sleep When Possible" unchecked? (which means your external and internal drives run ALL the time).  And  the only way your computer goes to sleep is by you manually putting it to sleep?

This seems like a huge departure from the way Apple designed the Energy Saving preference.

Last night I manually putt the iMac to sleep with the Glyph hooked up. This morning, the Glyph had powered off & dismounted as usual with the window display about "disc improperly ejected." So the re-setting of Sleep preferences didn't work. I called Apple again, was told that the re-setting of Sleep preferences was NOT the way to go, and perhaps if I tried hooking up the Glyph with USB instead of Firewire, the problem may get solved. (And I have restored the default "sleep" settings.) So I will try the USB experiment next week and see.  I have to wait until next week because the Glyph will not power back on until it's had a chance to rest for several hours. I was also told that if the USB experiment doesn't work, a "re-set" (invoving backing up the whole system w/Time Machine) was in order and Apple could talk me through it. (I reminded Apple that this problem with the external h.d. predated my upgrade to Mtn Lion.)

Ernest, could you describe the USB reset re-set experiment?

Not sure what you mean, but here is what a tech person at Apple told me to do: Under System Preferences Go to second row of symbols, click on Energy Saver, take both sliders to NEVER, ignore the warning with OK, uncheck "Put Hard Disk To Sleep When Possible," uncheck "Allow Power Button To Put Computer To Sleep." THAT DID NOT WORK. So I undid it and next week will try hooking my Glyph drive to the iMac with a USB cable instead of the Firewire cable I've been using. If the Glyph continues to power off/dismount, a second Apple technician says a "re-set" will be in order. I am not yet sure I want to go through with a re-set, may instead choose to disconnect the Glyph whenever I'm not using it. (I need it only to store video files and access them, which is not a daily task.)

I think I confused your comments about a "USB experiment" with a "re-set" (invoving backing up the whole system w/Time Machine). What did they mean by re-set? I'm a 20+ year vetern of Mac computers and I'm not familiar with how that term applies to this situation.

I think by re-set they mean uninstalling Mtn Lion and re-installing, which would require the back up in advance.

I had the same issue with Mountain Lion 10.8.3 (improperly ejected hard drives, Seagate 4TBs in my case).

A firmware update from Seagate solved the issue.

I am on hard drive #3, brand #3 (Lacie, Seagate, Western Digital) and still getting these errors using Firewire and USB (I am convinced this issue directly damaged my Lacie drive as a result of the constant unmounting). I am unable to backup using Time Machine because it won't run long enough to actually back up my HD (500 GB worth of data). I've tried every solution in this thread for nearly 7 months, popping in frequently and seeing absolutely nothing come of this serious problem.

The only thing that I have determined in my several hundred dollar needless wallet raping is that the problem is directly connected to Time Machine, as I now have a plethora of useless hard drives to hook up to my computer - none of which (other than the Time Machine drive) get ejected. Only the Time Machine drive. Partitioning doesn't matter, either. Whatever drive is assigned to Time Machine, that is the drive that unmounts.

It's not only disappointing, it's profoundly idiotic that this not only continues, but they continually rehash and tell people to perform tasks that clearly don't work.

Even beyond frustrating is that I see that after a years' worth of troubleshooting - Apple is unable to address this problem and my only hope is that I don't lose any more data between now and when the new OS comes out so I can sink more money into my poor functioning Apple product to make it operate normally as it should have out of the box.

Hi everyone,

i have been encountering this problem for some time myself.

i tried everything from connecting the drive directly into the sled, to changing the cases on my external disks, to disabling spotlight indexing and notification centre.

The result- still ejects.  Which led me to the conclusion that this may very well be a USB power issue and not an OS issue.

Took a trip to the local computer store and purchased a NextStar USB 3.0 powered dock.

It has been connected to my laptop via the same method as the old case- via a USB hub and it has not disconnected a single time in 10 days.

$19 to fix a problem that had me ripping out my hair for months. While the expenditure is not ideal, my aching head thanks me for it.

Power Cycling was the problem.

A Hub is definitely a better solution. I would also reset SMC/PMU