So thanks to you, Pisonia I've learned something that could be useful to others. My MacbookPro was was going to sleep normally, but after 2 hours the glowing and dimming light would go completely black. I had already done a SMC reset that did not solve the problem, but this time I let the computer restart and chime several times (like 4) and now when my computer goes to sleep the light continues to dim and brighten all the time even overnight. But the best news is I no longer have the problem of my Time Machine drive being ejected!!!! It works perfect and I've test it several times...No improper eject!!
Thanks. Yeah, the take away here is to check if your computer is sleeping correctly or not. On a Macbook or MacBook Pro if the light stops dimming and then glowing after a couple of hours it is likely entering another mode (hibernation) and this is where it disconnects from the external hard drive. By resetting the SMC my computer started working correctly in sleep mode and as a result, the external HD stayed connected. Also when doing a SMC reset it didn't work for me until I let it restart/chime several times. Good luck!
May have some clue here. After lots of emails back and forth, Micronet (makers of the Fantom drives, finally sent me this message just now. I suspect the same thing is true of other drives (especially since Fantom just packages other maker's drives). My answer was absolutely yes.
I apologize for the delay in response. We've now replicated the issue, which appears to affect Macs with native USB 3. We will have new firmware to fix this issue begin testing within the next week; Would you like to receive the beta?
I was having a similar problem with my Lacie d2 Quadra 3TB. Just got a new iMac 27in with ML. Every 10-20 minutes I would get a message saying the ext drive had been ejected improperly, etc, but it would remain mounted.
I had been connecting the LaCie to the iMac by USB 3. Two days ago I switched to a Firewire 800 (with Thunderbolt adapter) and the problem hasn't recurred yet. But I don't leave my hd on and connected when I'm away from the computer, so I don't know about the sleep issues.
I've just bought a new iMac, which now has 10.8.2 installed, and am having the same problem with my external drives. All 3 of my external hard drives seem to automatically eject when the mac goes to sleep yet they remount when I wake it up but with the "disk wasn't ejected properly" message. This never happened with my old iMac so I can't wait for this to be fixed.
I think the problem lies with ML 10.8.2 rather than the hardware being used. This would explain why some posters who are using earlier versions of ML are indicating they experience no problems with their external hard drives waking up and recognising Time Machine whilst other users have the problem using the same drive.
If Apple monitor this site and collate user calls to their customer support service, then I suspect they know all about it. Apple are notoriously secretive even in an indusutry not known for its open and transparent communciation with customers.
I guess we'll just have to wait for them to fix it the next time they issue a software update for ML 10.8.2
I have been having the 'disk not ejected properly' problem on a new iMac with a 1TB Lacie hard drive connected via Firewire to the Thunderbolt adapter. The Lacie drive is used for Time Machine backups and whenever the iMac came out of sleep mode the error message appeared.
The solution I found with the Lacie drive is that the power on button can be switched to full on (the drive runs continuously) or mid-way (this puts the drive to sleep when not active). On my previous iMac running Lion there were no error messages. Now with the new iMac running Mountain Lion 10.8.2 the error message does not occur with the power switch full on - hope this is of some help.
I'm using two external hard drives with my iMac and get the same eject error:
1.) Seagate FreeAgent GoFlex Desk 3TB with USB 3.0
2.) Data Tale 8TB RAID array with FireWire 800 and USB 2.0 (four 2TB hard drives installed)
I'm running Mountain Lion 10.8.2 and just about every time I put my 2009 27" i7 iMac with USB 2.0 to sleep, the external hard drives eject. I get the pop-up stating that it was improperly ejected. Anyone know how to stop this? Wasn't having any problems in Snow Leopard.
When I'm using the Seagate drive, some times the drive "appears" to be mounted, but when I choose the drive inside of the Finder app, I can see my directory structure just fine, but there will be "nothing" inside of the folders. The only choice I have at that point is to reboot the iMac and unplug / replug the hard drive to see the contents again.
On the rare occasions that it does work, I'll be trying to move a folder with a few files in it from one area to another area on the hard drive and then the spinning beach ball of death will appear. Again, the only choice I have at that point is to use Command + Option + ESC and force quit finder and reboot the iMac to get it back again.
I purchased the Seagate FreeAgent GoFlex Desk 3TB from Costco in November 2012. The part number is 9ZQ2P6-500.
I've searched the Seagate user forum and found a long running thread on this topic, but it doesn't seem that the problem has been resolved. See link below:
Does anyone have any suggestions or tips on how to fix this problem?
I've tried to use the link below, but it loads a very outdated application that doesn't recognize the Seagate FreeAgent GoFlex Desk 3TB.
I've run Seagate Drive Settings app numerous times and tested the drive and it has always passed the Drive Test.
When I try and use my Data Tale 8TB RAID array under FireWire 800 or USB 2.0, I get the same results at the Seagate.
I called AppleCare today, and the tech helped me clear out the cache files in the Library folder and then had me reset the PRAM, but that didn't help my problem with the Seagate drive.
I've also double checked Energy Saver inside of System Preferences to ensure that "Put hard disks to sleep when possible" is unchecked.
The only thing I can come up with is that the drive is USB 3.0 and my iMac is USB 2.0, but from what I've read, USB 3.0 is supposed to be backwards compatible with USB 2.0.
The only other piece to the puzzle I can add, is my 2009 iMac internal 1TB hard drive was recalled late last year, and I took my iMac in for service. I told them about the problems I was having with the external hard drives, but they seem to think that it was unrelated to the 1TB recall. My 1TB hard drive was replaced under warranty, but the problems with my external hard drives continue.
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.
Had the same issue, here on my spanking brand new rMBP 2013, USB 2.0 drives stay properly connected when I put my Mac to sleep, but a USB 3.0 drive always complains that it was not properly disconnected. The only difference I noticed was that now on 10.8.3 the drive comes up again, and gets mounted properly, which was not the case in 10.8.2. So A slight improvement, but still unacceptable, Apple you should fix this! Its definitly a software problem!
Well, it may not be the total solution but I fancy its major step forward. Following these posts it seems that the problem concerned ML 10.8.2 and drives using USB 3 connection. The changes you report in the update to 10.8.3 would appear to solve my original problem.
I think I'll dive back in and order a powered external HD (returned the last one) using USB 3. Fingers crossed!