Can’t Unmount Linux Partition: Umount – Device is Busy

You may get a device is busy error when you try to unmount a partition in Linux using the umount command:

umount: /mnt/sda2: device is busy
(In some cases useful info about processes that use the device is found by lsof(8) or fuser(1))


This device is currently in use by a running program and you cannot unmount it.

Use the following command to try to find the process that is using your device:

$ lsof +D | grep /dev/sda2

Or with fuser:

$ fuser -vm /dev/sda2

You will get a list of the PIDs of the processes that are currently using this disk. Kill these processes:

$ pkill target_process

Or by PID:

$ kill PID

Try to unmount the device again:

$ sudo umount /dev/sda2

If this does not help, you can force unmount such a partition or device (which may cause data loss in open files). There are two options for unmounting a device:

• Lazy unmount: in this mode, Linux will hide the mount point from the system and wait for all of the file descriptors on the specified device to be closed.

  # umount -l /dev/sda2

• Force: forced unmount (often the only way to unmount an NFS drive which is no longer accessible).

  # umount -f /dev/sda2