Alright so i shouldn't have installed the DP. buut i did. (I've installed iOS betas 4-7 with no problems). anyway i want to revert back to mountain lion, not because the os is buggy but a lot of my apps aren't compatible yet. (I'm on a new mba haswell). ive made a bootable usb of Ml but every time i go to boot it by holding option key and selecting the usb, i get a prohibitory sign (circle with a slash) and the computer turns off after a min ive gotten rid of the recovery partition for 10.9 but i still have the problem. I partitioned the hd and tried to install to that but it just says 10.8 can't be installed on this computer. any help is appreciated!!