===== Cannot unmount USB drive =====


If you try unmounting a disk as follows (wherever you mounted it)

<code>sudo umount /run/media/username/FlashDrive
</code>
and you get an error //umount: target is busy//, it can be very annoying to find the process that is using something from the drive.

You can use `lsof` to check which processes are accessing the files.

<code>lsof | grep '/run/media/username/FlashDrive'
</code>
This will show you which process is using which file, which can be useful.