How to correctly unmount an external USB hard-disk?

Question

I have a problem both with mounting and with unmounting my USB hard drive. This appeared when I upgraded to 12.04. Since then, when I insert the HD I get a message:

Unable to mount FreeAgent Drive

Error mounting: mount exited with exit code 1: helper failed with: mount: only root can mount /dev/sdf1 on /media/FreeAgent Drive

So I try a

sudo pcmanfm

And open the file manager with the required rights. I then do my business and eject the drive.

The problem is, that when I shut down the computer then, it does not shut down. It remains on, just the window system gets shut down. Then I see a black screen with various undecipherable text going on and the computer is not responsive. I have to shut it down manually.

Another problem is when I turn on the computer. Before the window system is turned on, I get a message which goes approximately something like this:

media/FreeAgent Drive (my disk) is either missing or not yet available. Wait or press S to skip mounting

When I skip and do not mount the disk thereafter, I am able to shut the PC down without the before mentioned shutdown problem.

Please what should I do?

EDIT:

my etc/fstab file:

# /etc/fstab: static file system information.
#
# <file system> <mount point>   <type>  <options>       <dump>  <pass>

proc    /proc   proc    nodev,noexec,nosuid     0       0
#Entry for /dev/sda7 : UUID=2fbc1e96-8d74-485e-8077-91e98d2275cb       /       ext4    errors=remount-$
#Entry for /dev/sdf1 : UUID=646CFE7D6CFE48F6   /media/FreeAgent\040Drive       ntfs-3g defaults,nosuid$
#Entry for /dev/sda3 : UUID=308E15138E14D2E8   /media/OS       ntfs-3g defaults,locale=en_US.UTF-8    $
#Entry for /dev/sda2 : UUID=22004B9B004B7537   /media/RECOVERY ntfs-3g defaults,locale=en_US.UTF-8    $
#Entry for /dev/sda8 : UUID=bcb597e7-2400-4ce5-8ee8-c75f5b512b4d       none    swap    sw      0      $

Answer 1

You added a line to your /etc/fstab file to mount the drive at boot time.

Removing that line will fix the problem.