That is incorrect. You have to reboot into your desired partition with the OS version you want. Not quite a simple as Log Out and Log In, but easy enough. Hold down option key when booting or choose partition in Startup Disk before you reboot. Doyle On Feb 11, 2010, at 9:33 AM, Paul Moortgat wrote: >> Not in my experience. Simply partition your boot drive to have as many partitions as you need, and install one version of OS X to each partition. >> >> I have one for Leopard, one for Snow Leopard. They don't interfere with each other at all. As you know, if you are in one version of OS X and want to be in the other, you will have to log out on and log into the other, but that's no big effort.