Hi Alexey,

I think you and I have very similar problems except mine is on a hard disk instead of a USB drive. (see post "Error messages when loading persistent image"). The Knoppix shutdown script is written to suppress error messages for the umount commands so something might be going on there and we would not know it. One interesting test for your system might be to see if you can create a home directory on a partition of your hard drive and see if you still get the messages.

Regards,
Bill