Comment 0 for bug 1507448

In order to test Kubuntu 14.04.3 LTS desktop hardware support on my laptop I attempted to install it (via USB stick) onto a USB external hard drive, with the plan of booting off the external drive and leaving my internal drive safely alone. I figured I could trust the installer to be sensible.

What a depressingly fatal mistake that was...

The internal drive is now screwed up, it drops to grub rescue if I attempt to boot off it. Manually attempting to use grub rescue seems problematic, because grub rescue doesn't like the licence on the internal drive's grub files.

The external drive can't be booted either, because grub wasn't properly installed on it.

This happened when asking it to do a non-manual install over the entire external drive - including formatting. If I had done a manual install I would have avoided this mess by explicitly asking it to install GRUB on the external drive. Or, if the installer had warned me what it was doing with GRUB, like it does with other file system operations, I might have been able to avoid this mess.

This is obviously a really nasty bug in the installer. If it's asked to install with all normal default actions over entire disk /dev/sdX, it doesn't make sense to do that - except then screw up grub on /dev/sdY.