Comment 33 for bug 573477

Same problem here. Solved by adding to /etc/mdadm/mdadm.conf this line:
ARRAY /dev/md1 metadata=1.2 UUID=someuuid name=somename:0

/dev/md1 may be different for you. It' may be md/1, md1 or something.
I get someuuid by using blkid utility.
somename from mdadm --detail /dev/md1

To get information from dlkid and mdadm --detail you need to stop array first
mdadm --stop /dev/md1
and then assemble it again:
sudo mdadm --assemble /dev/md1 /dev/sdX1 /dev/sdY1
After that you will able to get UUID and array name.