Disk Drive ejecting itself

I find it very strange that it only seems to be happening to my external HDD drive. Flash devices work fine and my iPhone sync fine.
The disconnection after sleep does seem logical but mine disconnects and reconnects randomly, every 3-4 minutes. I never really use sleep on my MacBook or close the lid. I hope 10.6.3 is just around the corner with a potential fix because I can't back up at all until it does. Even Time Machine gets interrupted by the problem. Not having a recent back up makes me nervous!

I'm having the same problem, with both my time machine and external media drives. I've run through the posted options to no success.

I have the same situation with a twist. For about a year I've had 2 500 gb HD's plugged in through a USB hub. No problems.

Yesterday I bought a 2tb Toshiba HD and it unexpectedly quits.

I have replaced the cable and the problem persists--only for the new drive. The old drives remain. They are plugged in through the same hub! the older one stays, the newer one quits.

Finally just decided to sell my simpletech and purchase a lacie stark 500MB. No problems for the last (3) weeks. This might have something to do with differant drive and manufacturers. I hope apple addresses this in there next update.

I started to experience self ejection just now.
It is actually a brand new Seagate Freeagent To Go with FW800 and USB2, so I suspect that the drive is incompatible. Not completely faulty since the ejection happens to the FW interface only, the USB works like a dream.
Any other drives in my history (5+) were USB2 and had no problem at all.
Interestingly when I connect the drive to my MacBook Pro with FW800-FW800 cable, it ejects itself after a minute (except once, that was a happy time, I even copied over 170G of data to the drive). On my old black MacBook with FW400 (FW800-FW400 cable) it works longer, could span an hour interval. Also on the MacBook it disappears silently, no 'eject before unplug' dialog, which is standard on the MacBook Pro.

Since the drive is a cheap 250G I considering not going into return procedure. I feel no guaranty that it will work the same way in the shop, they might find it working properly and so I loose on postage and service time, could well reach the price of the drive.
Also I don't want to invest into an other FW800 drive before I could tell for sue where the problem is. I don't want to be a crash test dummy. I keep an eye on this thing and forget FW800 for the time being. The first test shows that it is unreliable. To me no joy knowing who's responsibility is this, to me it is faulty. Pity, but have to fall back to USB2.

Btw. Is there a way to change the self ejection behavior in the system? Some hidden system parameters controlling how hard the OS tries to reach the drive before giving up, or something? Or power supply control?
It would be better if it does not mount at all in case of problem rather than disappear in the middle of something important randomly.

I am getting so tired of my Seagate Freeagent always ejecting itself, and also recently upon booting Mac Pro doesn't recognize it automatically, which it used to do. The self-eject and "improper" error message have been from day ONE when I upgraded to SL. But TM seems to work OK, and my eyes glaze over reading all these messages about potential fixes. I think my only option really is more redundant backup, and to turn TM on only when I decide I want to backup. I have another external HD for storage, and updating it from time to time with folder changes seems the only simple answer. I wish Apple could come up with a fix for this. It only started with Snow Leopard.

I have the same issue using a Maxtor 1TB external via USB on a new 2.26GHz Mini. I recently replaced a 20" iMac and the Maxtor was connected via Firewire 400 with no issues. I also have a Simpletech 2TB USB external that hasn't had any issues on the Mini. Could it have something to do with Apple's current "green" status? The Mini is supposed to be very energy efficient and if it isn't putting out enough to keep the USB ports alive for higher power requirements, that could cause it. I currently have it connected directly to the Mini and have tried going through a powered USB hub as well but end up with the same results. Quite annoying. I was going to pick up a Firewire 800-to-400 adapter but since others are having issues with various connection methods, I'll hold off till a solution is revealed.

I just wanted to throw my hat in for this issue as well.

I'm running a Mac Mini with 10.6.2, and I've recently attached a 2TB Seagate FreeAgent Desk via USB. I've been getting the whole "Eject before unplugging..." error (can't remember the exact verbiage... it's the one with the red exclamation mark/symbol I think). It seems like the OS "loses" the drive, but doesn't remove the entry from /Volumes (eg. /Volumes/SeagateUSB) ... and remounts the drive as a duplicate (eg. /Volumes/SeagateUSB 1).

I've tried new USB cables, changed electrical outlets (even plugged the drive into a battery backup), different USB ports, Disk Utility -> Verify etc., and have tried disabling Login Items that access the external drive. Nothing has helped.

I'll add this... I do have another USB drive that I've NEVER had problems with... until today. It's a 200GB Maxtor One Touch III... today I had the same duplicate mount point issue. It has only happened once, so it may have been a complete fluke.

The Seagate FreeAgent Desk is the first external drive that I've formatted in OS 10.6. The other external drives (with the exception of the Maxtor anomaly today) have never had any issues (two WD FireWire drives).

This is a CRIPPLING problem, and needs to be addressed.

I have been having this problem too.

I have 4 external drives. Three are externally powered, one is USB powered.

Fantom Drives GreenDrive 500GB - externally powered
Acomdata 500GB - externally powered
Unbranded enclosure (reported as WDC) with 500GB drive - externally powered
iomega Select 500GB - USB powered

Varying problems across all the drives.

I have had the eject problems and I recently migrated my Time Machine information from the Acomdata drive to the Fantom drive because I thought my Acomdata drive might be on its way out. Time Machine migrated, now I have having problems with the Fantom drive - the same issue.

I have also had problems copying files to the drives too, I select a bunch of files and folders and it will then stop, telling me that there is already a folder in the destination drive with the same name (there was not).

Unreal.

Sort it out Apple, seriously.

I wish this issue would be addressed.

I'm using a late-model iBook G4 with 10.5.8. Within the last 3 weeks my external Seagate FreeAgent Pro Media connected via USB had been randomly ejecting when accessing data such as playing music using iTunes or transferring files over my network using FileZilla it just ejects and the transfer fails and i have to reboot the HD before OSX can mount it again. I've been having the same problem described here countless times.

Please Apple fix this major issue, I can't make reliable full backups anymore. I have never complained about any software bug in my life. I want this one fixed.

it happens to me as well, only on my & other people's USB sticks (kingston, pendrive, etc.). I also have a FW800 HD (Western Digital) but never experienced this. it started when i switched to Snow Leopard on my MBP 15".

Same problem here, since I upgraded to SL. MacBook Air with 10.6.2, external drive Verbatim JH8709, USB-powered.

Any updates about this issue?

I'm having the same problem with my Lacie 300790U 250G hard drive since installing SL. It occurs whether I use TM or turn it off and use SuperDuper. Called Lacie and all they could recommend was getting a new AC adapter. Am using a firewire 8 connection only, but others seem to be having the same problem with USB, so don't see much point in trying that. Anyone solved this yet?

Seems that it is at least primarily a Snow Leopard issue. No idea what could cause it other than some energy saving feature on the USB ports that some of these drives can't cope with, causing them to 'disconnect'.