Re: Using wubi to install ubuntu on a usb drive
See no point in using Wubi if that is going to be the only OS on that drive. Wubi's main purpose is to prevent you from having to do partitioning. If you're doing that anyway on a USB drive, you would do better doing a traditional install.
Also, if you are running Windows on your internal drive, then do NOT have it connected when you install to the USB drive to prevent accidentally writing GRUB to your Windows drive.
Ubuntu 15.04 Mate, Mint 17.1; MS Win 8.1, Win10 TP.
Will not respond to PM requests for support -- use the forums.