Device is busy

From Computing and Software Wiki

umount ---"device is busy!"

When using Linux, after finishing using CDROM or floppy disk, when try to un-mount them, sometimes users may get an error message "device is busy".

In this situation, first, make sure you are not in the /mnt/floppy or /mnt/cdrom directory when issuing the "umount" command. Second make sure no file and directory in the floppy disk or cdrom is used by any applications. If you still get the "device is busy" error message, "fuser" command may be used to further trouble shooting.

Command "fuser -u /dev/fd0" or "fuser -u /dev/cdrom" will give you information as which processes and users are using the floppy drive or cdrom. Then you can kill the processes. This may help you to unmount the device.

You may also use the command "fuser -k /dev/fd0" or "fuser -k /dev/cdrom" to directly kill the processes which are using the filesystem.