4869 Views 5 Replies Latest reply: Oct 2, 2010 9:36 AM by phpguru
In my experience this is usually a mechanical/physical issue. It may be the an ill-fitting cable terminal, a USB port either on the computer or the HDD, or a problem with the USB bridge on the drive itself. If successive drives and cables don't eliminate the issue, it may be with the computer itself.
Are these drives bus-powered (no separate power brick; sometimes called "portable" class drives) or self-powered (have a power brick)?
If they are bus-powered, they could be asking for more power than the MBP's USB ports can provide. If that's the case. consider buying a self-powered USB hub (again, has a brick) and installing it between the computer and the externals.
Yesterday I found that OWC has a hub on sale that works in both portable bus-powered mode and in self-powered mode. Best of both worlds:
i may have a solution for this. my working theory is that the drive is going to sleep on its own, and snow leopard interprets this as an improper drive ejection. after hunting around for several hours, i finally found and downloaded the Seagate Diagnostics application for the Free Agent drive family. After running the diagnostic test, the problem went away. i read that (despite the uninformative name) this application installs a driver that manages sleep in a way which is compatible with snow leopard.
@Gizmolab - Thanks for that reply. It seems like a decent theory. I found Seagate Diagnostics for Mac. It says it's only for drives that have a FireWire800 port. The ones I am using have USB only. I installed it anyway. When I run diagnostics it says no drives found so I cannot diagnose them. I'll see how it goes though, maybe it updated the driver.
To add some more info to this thread... I figured I'd try Disk Utility to manage the drives manually. I've tried dismounting them and also just dragging the volumes to the trash when they are not in use, and using Disk Utility to mount them again when they are needed.
What I've found is that in addition to the drives automagically ejecting themselves (and remounting again automatically about 20 to 30 seconds later)... is that a dismounted drive will automagically mount, too. Okay fine, I'll dismount them and unplug the USB cables, and reattach them when I need them.
Disk Utility reports that there appears to be no problems with the disk... thankfully. While typing this reply, I heard the disk go to sleep and about 3 minutes later it just ejected itself dang it. So Seagate Diagnostics appears to be only for Firewire800 drives.