Comment 12 for bug 695842

Installing to /dev/md0 is certainly wrong in the (typical) case where the array is constructed from partitions rather than whole disks. The installer does have code to spot this situation, which evidently isn't working for some reason.

Could you run through an installation that reproduces this, but before you reach the GRUB installation step, switch to Alt-F2, 'nano /usr/bin/grub-installer', uncomment the 'set -x' line near the top, save and exit, and switch back to Alt-F1 and continue? This should give a more verbose syslog which may uncover the problem with situation 3.