Mac OSX tricks 1 : cannot empty your trash ? use lsof

01 January 2010

So you want to empty you Trash but you have this below message saying that the file is already in use.

You click continue but the file isn’t deleted.

In this case, the problem is that the file is a dmg and is mounted.
You just have to unmount the image to be able to delete it permanently.

But in some cases you don’t really know what’s the process currently using your file(s).

Here’s come lsof !
If you open the lsof man, you’ll read : lsof – list open files
So if you just type lsof without any arguments, it lists all open files by all processes.

lsof also take one or several files in argument so it can list all the processes using this file(s).

$ lsof .Trash/Spotify.dmg
COMMAND    PID USER   FD   TYPE DEVICE SIZE/OFF   NODE NAME
diskimage 1842 mike    3r   REG   14,2  3286498 928605 .Trash/Spotify.dmg

Here you can identify diskimage as the process using our file.
Now that you know the file is mounted, you can unmount it using the finder or the command line :

$ diskutil unmount /Volumes/Spotify

Or simply kill the process (in this case it will unmount it) by using the PID nicely given by lsof :

$ kill -9 1842

You can now empty your Trash.