Yes. On system boot, Ubermix wipes all data in usb keys and external hard drives.
It took me some work to figure out what was happening after I lost data in some usb keys.
The /etc/rc.local script, which is run on boot, contains this dangerous command:
rm -rf /media/*
Which is run when the connected keys or drives are already mounted...
I was lucky to lose only a few Ubermix and Clonezilla keys, but it could have been all my personal and work data.
It wouldn't surprise me it already happened to other people...
Eveything else in Ubermix is lovely but I really think this needs a fix. Seriously, it's too dangerous.