Background

Solving disk problems is a little more complicated when devices are encrypted. You need to keep in mind that a filesystem on an encrypted device can’t be seen unless the device is decrypted. Here is a few problems I’ve come in touch with, together with solutions that have worked for me.

Error unmounting a volume

Error message which may occur when trying to unmount truecrypt volume:

Trying to remove the volume with cryptsetup gives a similar message:

As the error messages implies, something is keeping the volume open. If lsof doesn’t show anything, it might be an active NFS export keeping it busy.