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.