ok well in that case the USB pen drive is already mounted and I imagine the unmount option simply allows you to safely remove the pen drive.

I have looked in the instructions to make an image backup (link below) and I'm able to follow ok but I cannot change the backup location to usb. The instructions say to do the following:

"press MENU then using the left and right buttons on the remote you can change the location"

When I press left/right nothing happens, but the usb is definitely mounted ok because I can make recordings to it!

LINK for instructions
http://openvix.co.uk/openvix-builds/...0ViX%203.0.pdf