Yesterday I tried to downgrade to mountain lion from maverics but it doesnt work !! i have mountain lion on my sd card as boot drive and when i try to use it, my screen shows a circle with a cross in it. also i erased my hard drive in disk utility before i did it. i also saw something else on disk utility that had the osx maverick on it but the option to erase that was greyed out. is it because i have fusion drive and the hdd is seperate? i dont know ! but that part wasnt erasable and ya i really need help badly ! i am so sad . back when i had mountain lion ,, everything worked PERFECTLY. after getting mavericks , i want to kill myself because my computer keeps randomly lagging when i am browsing files in finder and the worst part is it keeps lagging in photoshop and its driving me crazy because i work in it all day ! someone have a solution please?!?! ahhhh i reallly want mountain lion back , i tried to be okay with mavericks but just cant !!!!!!!