Comment 8 for bug 504173

Could you please edit the file /usr/sbin/grub-mkconfig and add an 'x' at the end of the first line.
change
#! /bin/sh -e
to
#! /bin/sh -ex

The open a terminal and run
(sudo /usr/sbin/update-grub 2>&1)>update-grub.log

And attach the file update-grub.log to this report. Thanks.