If you have an earlier G4 (<450mhz), that isn't "supported", but change the processor min. in the plist file, and it'll work fine. I'm running it perfectly (and quickly) on a G4 400mhz - I have no idea why this machine isn't supported out of the box, it works great. Don't think this will work to go down to a G3 though, but for early G4 users, this works.