How to unmount a USB drive on Ubuntu. If you have mounted a USB manually, it is best to even unmount it manually. Step1: Use the following command in order to unmount your USB: $ sudo umount /dev/sdb1. And also: $ sudo umount /media/USB. In the above command, specify the mount point if it is something other than the ‘USB’ mount point I have used.Why does unmount fail in Linux?
The unmount will fail. It failed because the current working directory of the user is within the file system he is trying to unmount. Linux is smart enough not to let you saw off the branch you’re sitting on. To overcome this use the -l (lazy) option. This causes umount to wait until the file system is able to be safely unmounted.How do I unmount a hard drive in GNOME Disks?
To unmount a hard drive in Gnome Disks, start by looking at the left-hand sidebar. This sidebar has every detected disk on your Ubuntu PC. Everything from hard drives to USBs, to SD Cards, will be here. Look through the sidebar for the hard drive you are trying to unmount.How do I force an unmount?
Use the -f (--force) option to force an unmount. This option is usually used to unmount an unreachable NFS system.