For some reason that is as yet unknown to me, my external usb drive unmounts once in awhile. I can't figure out what's causing it, I can't figure out what prompts it, and I can't remount it unless I completely restart the computer. Unplugging it and replugging it doesn't work and it doesn't show up in the Computer window to remount. It's getting sort of frustrating.

My sda1 partition never unmounts (which is my Windows partition on my internal hd), only my USB external. I haven't had a thumb drive in there long enough to tell if it does the same thing, but I might see if it does if the problem persists.

The USB drive is on a D-Link USB hub, if that makes any difference. I'd connect it directly to my comp if I could, but all of my ports are usually being used.

In any case, is this a known problem that can be fixed?

Instead of plugging in the drive and unplugging it try working from the command line. Issue the mount command to see what you have mounted:

mount

and then try to unmount the USB drive using the umount command:

umount /dev/sdb1

or whatever partition the USB drive is mounted as.

Once you get the USB drive umounted you can try to mount it by replugging it or you can try to mount it from the command line.

----------------------
Steve Stites

Should I be able to remount it through the command line by typing in "mount /dev/sdb1"?

Yes, assuming that the address is /dev/sdb1. You can find out the correct address by using the mount command without any parameters. See:

man mount

--------------
Steve Stites

There's another question to ask. USB devices can be seen by the system but not mounted. Run "lsusb" to determine what devices are recognized. If when your device unmounts it's also no longer detected you have a intermitant hardware problem.

Thanks, the next time that happens I'll do that.

Alright, I have an update. It took awhile for it to happen again, surprisingly. But, anyway, here's what happened; I'll go ahead and explain some other eccentricities in case they're related:

This time it didn't unmount unexpectedly; instead, I restarted my computer and it didn't even mount at all. On my desktop, I saw two icons for the same CD (only one drive). I right-clicked one and hit eject, and it ejected, but only ONE of the icons disappeared. The other stayed and gives an error when clicked on and nothing when told to eject.

Here's what's probably the most important: I typed in "mount" and the external drive is not even listed. I typed in "lsusb" and it IS listed. I typed in "mount sdb1" (and sdb1 IS the hd, I didn't just copy-paste what you said ) and it said "mount: can't find sdb1 in /etc/fstab or /etc/mtab." I typed in "umount sdb1" and it said it's not mounted, unsurprisingly.

This may not help much but a given device can be mounted under different names and would appear twice on the screen. The system creates four unmounted mount points for my DVD RW -- /dev/cdrom, /dev/cdrw, /dev/dvd and /dev/dvdrw. In my case all of these mount points are links to /dev/hdc.