Your usb drive is corrupt. You will need to recreate it and should run the check disc option from the boot menu to verify that it is working correctly.
** Changed in: ubiquity (Ubuntu) Status: New => Invalid -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1400700 Title: Failed upgrading ubuntu 14.04.1 with 14.10 usb drive To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ubiquity/+bug/1400700/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs