Here's an interesting one for the hardware gurus. I have a 2 TB Seagate USB 3.0 drive. It came formatted as NTFS by default but I wanted to use part of it for daily rsnapshot backups, so I repartitioned the drive thusly: 1.6 TB NTFS, 400 GB EXT3. When I plug the drive in, Linux Mint 13 sees and mounts both partitions successfully. When I'm finished with the drive the fun starts.
If I click on "Safely Remove Drive" of the NTFS partition on the desktop, Mint unmounts both partitions just fine - usually. Sometimes it decides to remount both partitions after a delay of 30 seconds or so. If I plug the drive in again.. nothing. I start seeing messages like this:
[ 1716.328039] xhci_hcd 0000:02:00.0: Timeout while waiting for a slot
[ 1716.328047] hub 4-0:1.0: couldn't allocate port 2 usb_device
The drive isn't even recognized until I reboot.
Now if I click on "Safely Remove Drive" of the EXT3 partition, that partition unmounts, but the NTFS partition gets.. hung. I get bizarre messages like this:
Sep 18 20:48:37 ian-home ntfs-3g: Unmounting /dev/sdd1 (SG2NTFS)
Sep 18 20:49:38 ian-home udevd: timeout '/sbin/blkid -o udev -p /dev/sdd1'
Sep 18 20:49:39 ian-home udevd: timeout: killing '/sbin/blkid -o udev -p /dev/sdd1' 
Sep 18 20:49:44 udevd: last message repeated 5 times
Sep 18 20:49:44 ian-home kernel: [ 5809.832246] sd 14:0:0:0: Device offlined - not ready after error recovery
Sep 18 20:49:45 ian-home udevd: timeout: killing '/sbin/blkid -o udev -p /dev/sdd1' 
The drive also ends up unusable until I reboot.
Prior to repartitioning the drive, Mint was fine with it. Unmount, unplug, plug back in, remount, I could do it all to my heart's content.
Anyone have any advice? Even if it's "Go buy another external drive and make it solely EXT3 and save yourself the hassle"?