This has probably been asked and is probably very simple but I have been searching online for a couple of weeks now. I have an older Imac that has Lion but cannot update to Mountain Lion, not capable. I found where I can use a program and make a partition and do it that way, however, I need to download a copy of Mountain Lion onto the computer that I want to be able to run it from. If I go from the app store it tells me program not compatible. If I try to copy it or zip it to a flash drive, it tells me too large. Help. I know this is probably an easy thing, but I would love an answer! Thank you!