I'm experiencing an issue when using the "Safely Remove" option to remove my 1TB external HDD from the Unity Launcher. Not every time, but occasionally my screen will go black and display LARGE amounts of text information (which I obviously cannot screen cap). The jist of the info displayed is that unmounting or 'safely removing' the drive causes a kernel panic. Is there a Command Line command to remove mounted drives, or at least one that would show me some sort of error output when the drive is removed? I'm trying to narrow down the cause. I could be imagining this, but it seems to happen most often when I have other programs running when I remove the drive (i.e. Firefox, Transmission). Please note that my external drive is not in use when I attempt to remove it and it is not being used either by Firefox or Transmission at these times. Any help would be appreciated.
Hopefully I'm posting this in the right spot, but I wanted t to thank everyone for their answers and say that I was able to solve this issue by installing ejecter from the repositories.
I turned off mounted drives in the Unity settings and now use ejecter to remove the external HDD. All seems well now and I just thought I'd share this workaround with anyone else who might have a similar issue.
No matter how you unmount your drive, in the end the kernel will be responsible for the actual hardware; since it panics from the user interface, it will most likely panic from the command line, too.
Your very best option would be to follow the instructions at How can I get a Kernel Core Dump and post the core dump to the ubuntu kernel maintainers.
Your second best option would be to try to "single step" the unmount process from a root terminal:
Then see at which step it crashes and retry the same without step 1 but with a manual read-only mount.
The most trivial thing to do is however confirm if your TB Drive is in need of a fsck. Note that if it is NTFS-formatted from Windows, the linux fsck can only flag it for check under windows because the real check can't be implemented in free software due to some proprietary reasons.
On a side note, generally external drives don't get mounted with FUSE; if there is a driver available, you could mount it with FUSE and only the user mode filesystem would crash leaving the remainder of the system alive but I cannot guarantee anything in that direction.