Linux MINT 18 Live Image

I have a Linux Mint 18 Cinnamon installation, created a ISO with the "Backup" method to include all user settings.
ISO creation was succesfull, burned the ISO to a USB flash disk with Unetbootin.

Booted from this USB, select "live".
During this boot from USB i receive
"/cow format specified as aufs and no support found"

What do I need to change to get it succesfully booted?
thanks

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additional info:
kernel is 4.7.0-040700