i have created a dual boot (both OS are Kubuntu 12.10 and both with encrypted home don't ask me why, i just wanted to try the pre-boot authentication of Grub2) and i've created a partition table like this:
/dev/sda2 /root Kubuntu1
/dev/sda3 /root Kubuntu2
and installed Grub2 in /boot partition. Then I've modified Grub2 40_custom adding superuser and 2 users (one for the kubuntu1 and one for kubuntu2) as shown in this guide:
in order to boot with preboot password BUT only super user and kubuntu1 users works. When i try to enter the second user it says:
"Access denied: Loading the default entries and list failed"
Any suggestions about that?