I have Knoppix 5.1 on USB Key. When I boot the key, I select the 2nd option:

SYSTEM: Add as persistent writable system area.

Everything works great, it saves every changes and new stuff on my USB Key (Persistent mode).

The next time I boot from the key, I get a message:

Knoppix.img was not cleanly unmounted.

Then it fixes a bunch of inodes, block and whatever else.

I don't notice anything wrong in Knoppix. It's just drives me nuts that is does that everytime I boot.

Is there something I can configure to help Knoppix to cleanly Unmount?