Q: External Hard Drive spontaneously ejecting after upgrade to Snow Leopard

I am having similar issue except I have not upgraded to Snow Leopard. Still on Leopard 10.5.8. Last week bought two new external hard drives. Both WD My Book Home Editions..one 500gb the other 1tb. I am using the 1tb for
Time Machine and have had no issues with it. The 500gb has been ejecting after the computer has gone to sleep and I end up needing to power down the HD and restarting for the it to remount. Thought the HD was faulty so I returned and got a new one. Same issue popped up this morning.

OK, since setting my machine not to sleep this hasn't happened so clearly it's sleep that's the problem (for me anyway).

When I was on 10.5 my machine was never set to sleep so, as mentioned above, might not actually be due to the SL upgrade.

cheers

James Closs wrote:
OK, since setting my machine not to sleep this hasn't happened so clearly it's sleep that's the problem (for me anyway).

That seems to be the case for me as well. I've been tracking this for three days - Noting when I've put the computer to sleep, how, and for how long, and how I wake it, and what TM Preferences Window has to say. There doesn't seem to be any rhyme or reason about this - the computer can be asleep for many hours, overnight in fact, and wake without ejecting the TM drive; it can be asleep for 5 minutes and eject it. The ejecting happens whether the "Put drives to sleep..." is checked or unchecked.

I have noticed that when I allow the computer to go to sleep on its own, it takes between 10 and 15 minutes for the power light to go to blinking mode. Initially I have a solid light. If I wake the computer while the light is solid, it wakes fine without ejecting (and I can wake it by moving the mouse). It seems that the ejecting is more likely when the power light is blinking (that's true even when I've gone to sleep using the power button). No matter how the computer goes to sleep (power light blinking), I can no longer wake it by moving the mouse, I have to click the mouse or hit a key.

When the computer wakes without ejecting the drive, the TM Preferences say: "Making backup disk available...", then "Calculating changes...", then it does the backup - but it doesn't always do the backup immediately, it sometimes waits until the next scheduled time.

When the computer wakes and the TM disk is ejected, the TM Preferences say: "Next backup when disk is connected...", it connects the disk - it shows in my case, blue, on the desktop, then "Calculating changes..", does the backup - I'm not sure that it does the backup every time when the TM disk remounts - that's the next thing I have to watch for - I didn't catch that in my notes.

Been fooling around with my setting too.

In power settings set computer to not sleep. Had no ejection issues.

Then turn TM off but let computer sleep. External drive had no ejections.

Turned TM on and let sleep. Couple of times no issues but then external drive was ejected. Best guess I have is that if TM is backing up the external drive when it is being waked then the external drive is ejected.

I am going to try and test this.

It's not to do with Time Machine as I'm not using Time Machine and still get the problem.

Hasn't happened once to me though since I set the machine not to sleep.

My advice on this is to call Apple. I was in touch again yesterday - got through to a supervisory person. She helped me capture and transfer info from the logs to pass on to the engineers. Apple is aware of the problem. I discovered yesterday, that turning TM off but not dismounting/ejecting it myself, didn't stop the problem - TM turned off and the disk image still dismounted improperly. So for the moment, I'm not putting the computer to sleep. Waiting now for Apple to get back to me.

James Closs wrote:
It's not to do with Time Machine as I'm not using Time Machine and still get the problem.

Hasn't happened once to me though since I set the machine not to sleep.

James, you're right. It's got to do with "sleep" whether you use the power button or allow energy settings put the computer to sleep. The external drive is being ejected whether it's being used for TM or for some other kind of backup.

I also have this problem. It persists after the Apple tech told me my drive was bad and I purchased a new one. I'm not pleased.

The new drive cannot be repaired by disk utility as it is hopelessly corrupted after one complete TM backup.

OK, I'm wrong. It just happened to me again when the computer was set to never sleep.

So - sleep seems to massively exacerbate the problem, but the problem persists. I went for several days before getting a spontaneous eject (sounds like something I should visit the Doctor about really)!

I too am having this problem and to make things worse I'm also getting spontaneous keyboard freezes (as if the USB cable was unplugged)

I've tried a wide range of different ports, including adding a PCIe expansion card so there are no hubs in use.

so far it's corrupted my Time Machine Backups. I'm worried it will screw up my Photos (external USB disk) and my data backups.

I used to have eSATA before SL excluded my eSATA cards - I thought USB would do as a fallback, but waking from sleep to see the dread not properly ejected message is becoming unfunny.

Disk Utility couldn't repair my corrupted drive either. I used Disk Warrior and it did. It didn't solve the problem, but it recovered the data. Unfortunately Disk Warrior is a bit expensive.

I have exactly the same issue but only when I connect my external hard drive through a USB hub. If I plug in the external hard drive into the USB port of my mac directly it seems to be stable.

Amit wrote:
I have exactly the same issue but only when I connect my external hard drive through a USB hub. If I plug in the external hard drive into the USB port of my mac directly it seems to be stable.

Mine, and several others, have the TM drive plugged directly into one of the computer USB ports and are having the ejecting. So you're lucky!

Just wanted to chime in to say I'm having the same issue. Just upgraded my wife's iMac to 10.6.1 and added a Lacie USB external (with 2 partitions - one of which is a Time Machine backup) directly connected. External has it's own power source and is connected to a UPS. Get the "disk not ejected properly" warning every time on waking from sleep.

I've never had this issue with other externals before the SL upgrade. I would suspect the drive, but it seems like others are having trouble with various types of drives - so it seems like a Time Machine or SN issue. I'm going to try turning Time Machine itself off to see if that solves the problem. Then I'll try some of these other suggestions and see if I can help narrow the issue down...