Hello Dave, Is your MDD a Firewire 800 model? If so, you will not be able to boot up natively in OS 9. Only the Firewire 400 MDD's without Firewire 800 can boot natively in OS 9. If your MDD is a Firewire 400 only model, then you need to get the gray colored software install disks that were shipped with the Firewire 400 MDD's. The retail edition of OS 9 will NOT run on MDD's. I own 3 Firewire 400 dual boot MDD's and found out the hard way. You might be able to find the Firewire 400 MDD software install disks on Ebay. Hope this helps. On Apr 8, 2010, at 5:19 AM, Dave Dent wrote: > Hi I'm new to Mac. I want to run a dedicated system just for > Protools 5.0.1. I have a G4 MDD 1.25 DP running OS 10.5, I need to > run OS 9.2.2. I have a 4 disk recovery set (OS 9.2.2 & OS X) but > that is not working, it keeps telling me after the first disk > "communication error, check helper tool, application bundle"? I > would like to buy an original OS9 disk can you lead me in any > direction? " > _______________________________________________ > G4 mailing list > G4 at listserver.themacintoshguy.com > http://listserver.themacintoshguy.com/mailman/listinfo/g4