View Full Version : Time Machine EATS DRIVES!!!

May 22, 2011, 09:18 PM
I've got an external USB-powered 320G iOmega drive on my wife's mini that's used for Time Machine that frequently disappears from the desktop, preventing TM from backing up. I'll unplug and replug the drive, and it appears again, and can be selected for TM, and all is well. The last drive I used for this suffered the same symptoms and eventually failed and could not be repaired.

Is there something that can prevent an external USB-powered drive from surviving a restart, or mysteriously get interrupted somehow? Or cause it to not be automatically restored to the desktop after that happens? Is there a way around this? I have my own TM setup which uses my TimeCapsule, so could another mac somehow get confused and forget a local USB drive to try to use a nearby TimeCapsule instead?

Anyone else have this problem or hear of it? Or have any suggestions?


May 23, 2011, 03:28 AM
It is possible that the Mini has a faulty USB port that is causing problems. It could be dirty power at the socket. Check the syslog for messages relating to USB.

If possible try using a FW external drive.

May 23, 2011, 08:00 AM
I had this problem with 2 500g Iomega drives... Both were USB 2 in the thin silver metal case... The problem was the enclosure. I bought a new enclosure for both the drives and have had no problems since.

May 23, 2011, 10:21 AM
I have seen this issue with Iomega drives frequently. A new (even extremely cheap) enclosure for the drive solves the problem.

May 23, 2011, 07:03 PM
I use a 320gb iOmega drive.
They seem to be popular.
I never heard of them until I wen to go get it for my time machine.
I haven't had any issues with mine.
I just hate the fact time machine backs up every hour.
Maybe check your cables and your ports.

May 23, 2011, 07:52 PM
I had a 500 GB USB or firewire external drive that had the same symptoms (occasional dismounting, then remounting to the desktop).

I threw it away.

The money involved is not enough to make it worth trying to fix, and the data on my machine is important to me. I went out and bought a 3 TB for $180 or so at Best Buy on the way home from work. That cost me 1/2 hour, let's say my (your) time is worth $100 an hour. So I spent $230 (=180 + 100/2) and removed that particular worry from my life.

May 24, 2011, 10:14 AM
This is definitely a power issue with the external drive/enclosure.

I've run into this quite a few times now as I've upgraded laptops and reused old hard drives by putting them in various makes/models of enclosures.

Many of the generic USB drive enclosures on the market try to solve this power problem by using a Y-splitter type USB cable that requires 2 USB ports. That way, they send the actual data down one while they get extra power from the second one. That typically works, but wastes ports.

Others, like the Western Digital Passport series of enclosures only attach with a single USB cable, but you'll find that some Macs can't provide enough power on their USB ports to spin it up properly/reliably. The Powerbook G4, for example, was notorious for not being able to run them properly.

On a desktop system, I'd honestly recommend sticking with external drives that include their own AC power adapters (and are usually bigger, bulkier units that take desktop-sized SATA drives, vs. laptop style drives). They're going to be more reliable and will eliminate the power issues.

May 24, 2011, 02:19 PM
Time Machine works perfectly with my external drive.

Note, with external drives, after ejecting, you should wait a bit for the drive to spin down before disconnecting.

If problem with drive, do verify disk.