Hi All,

Normally I can right-click on the desktop icon for this external drive and unmount it, and all is good. Today when I try that, I get the message "can not unmount, an application is preventing it". When I try to unmount with the command line I get message the the device is busy.

There are no applications open, and I can see nothing running when I open my system monitor. I know from past experience if I turn off the PC without unmounting properly, I will end up with broken links I have made on this drive, which leads to much work redoing all that.

Any ideas what I can do to safely unmount this drive?

Thanks for all help.

First thing, make sure you aren't using a directory on that disk as a current working directory. (If so, cd out of it.)

Otherwise try a "lazy" unmount using the -l option. (My guess is you have to do this as root, so put a sudo command in front of it. I think if you then power down the machine normally, everything should be OK.

From the umount man page:

You can also kill whatever is accessing the directory like this (as root, of course):

fuser -k [directory] (for example, fuser -k /home/username)

Of course, this won't work if umounting is failing simply because you are still inside that directory; as pointed out, above, a "cd" will take you out of the external drive and back to your home directory.

Thanks for the replies.

This is what I did, and what results I got. The final command, when I typed it correctly, seems to have unmounted the external drive. FYI, I did not have any directories open, so still not sure why I was having the problem.

Thanks for the link to the Man page with the descriptions of umount. Very helpful. I will have to spend some time on that page. This is not the first time someone has referred me to a great page like that on LQ.org that I did not know existed.

Thanks for the help. Now I will reboot, and see if all is OK with that drive.

Oh yea!

The lazy umount did the trick for the external, though the PC would not shut down. I had to unplug it, then boot up, but the external drive and links survived, so I am happy.

Many thanks.

That sounds like a bug. You might want to report it if nobody else has. The Ubuntu website has info about reporting bugs.

FYI, you should have a set of man pages on your local machine as well. To view the page for mount (for example) you would open a terminal window and type:

Most of the CLI commands should have a man page you can access that way.