I have similar problems with latest Ubuntu Vivid daily build (2015-04-16: http://cdimage.ubuntu.com/daily-live/current/vivid-desktop-amd64.iso) installed on USB media. In boot I see messages "invalid user: ubuntu ubuntu".
I have similar problems with latest Ubuntu Vivid daily build (2015-04-16: http:// cdimage. ubuntu. com/daily- live/current/ vivid-desktop- amd64.iso) installed on USB media. In boot I see messages "invalid user: ubuntu ubuntu".