So I got 10.5.6 running on my AAO along with Win XP dual booting. I would like to upgrade my Mac OS to SL but when I tried to follow the instructions in this forum, I get stopped when I try go pick the disk partition to install (update) because it says that I must have GUID partition table scheme and I am using a "master boot partition" scheme. Is there any way to fix this short of reformatting the entire drive and loosing all that I have working currently?