Background: I have a MacBook Pro with a 2.2 intel i7 with 4 GB 1333 MHz DDR3 When I click about this Mac, it says late 2011 and I believe I bought it on the apple website on Christmas Day of 2011. Anyways, I have Mac OS 10.7.5 with latest updates installed, I had rEFIt installed, and Ubuntu LTS. I believe rEFIt and Ubuntu LTS were latest editions. Then I bought Mac OS 10.8 in the App Store. I tried to install OS 10.8 and on reboot, the install didn't work so I rebooted and went back into 10.7 and renamed the efi folders to backup_efi. (This is how I disabled rEFIt). I was assuming that the whole rEFIt and Linux and partitioning the hard drive had something to do with why the install wasn't working. What happens next: So I tried to install 10.8 again and on reboot the 10.8 installer gave me this error: "An error occurred while installing OS X. You cannot install "OS X" on this disk. OS X cannot start up from this disk" (side note, this error looks familiar so it may have been the same problem I had installing it before I disabled rEFIt.) Then there is a place to select the disk where you want to install OS X I have 2 choices: 1) Mac OS X Install ESD (326.2 MB free / 4.78 GB total) 2 Macintosh HD (371.68 GB free / 529.3 GB total) Both have the triangle containing the exclamation point on their icons. When I select Macintosh HD, the message "OS X cannot start up from this disk." appears below the icons. Now my only choice is to click the go back button and either restart, shutdown. Oh wait I just found that if I click the apple in the top left I can select the start-up disk. Ok (sigh of relief), I'm able to get back into 10.7. The problem: I can't figure out how to update to 10.8, and I don't know exactly why it's giving me that error. Please help. Also the attached photo is appearing upside down in the "preview post" but when I edit attachments and click the image link it shows right side up. I'm not sure what's going on here but hopefully it doesn't end up showing upside down on here.