Ubuntu – Can’t format USB drive

formatumountusbusb-drive

I have a 4 Gig USB drive that I'd like to format.

I go to the Disk Utility, and try to format it, but it says that the device is busy. (This same error occurs no matter whether I tried to format the whole drive, or just the partition.)

So, I do some research, and figured out how to disable automount. It's now disabled.

To be on the safe side, I first unplug then reconnect the USB stick then tried:

sudo umount /dev/sdb
sudo umount /dev/sdb1
sudo umount /dev/sdb*

Now, the Disk Utility STILL gives me the same error – usually "/dev/sdb is busy" or "/dev/sdb1 is mounted" or similar.

Run df -h in terminal and make sure there is nothing mounted that looks like /dev/sdb*. I had /dev/sdb11/ and /dev/sdb8 mounted so I had to run umount /dev/sdb11 and umount /dev/sdb8.