Recently bought a 2nd hand mac pro. It had a beta Leo installed which for obvious reasons I wished to get rid of and use my retail Leo DVD.

I can't install it though. It fails about half way through with a message about eithe BSD's package or Essentials package. Upon looking around for a solution it appears it may be a memory issue (non apple ram). I swapped back in what I think is the original ram and the problem has persisted. I have tried and exhausted all the memory configurations available to me - the problem persists.

If I let the dvd disc verification run then surprisingly this fails saying my disc needs to be cleaned. Now this is a retail Leo dvd that has barely a mark on it. It has been successfully used on both of my old Macbooks without a problem. Whilst I see this COULD be the problem it seems a little odd.

I borrowed a oem grey install dvd from one of my works mac pro's (a more recent model as mine is an older 2007 model). This would not allow to be booted from (I hear this is common with these grey discs if not on the model they came from). It did thought boot to the installer with my Macbook. Odd.

Is there anyway I could use thus oem disc via the mac book (and potentiall external drive) to install to my Pro?

Any other suggestions? I'm loathe to have to pay out for a new Leo DVD when I'm not 100% sure that's the problem. There's barely a scratch on it!

You can probably take it to an Apple Store and the 'geniuses' will be able to help you out

Bit of a hassle with no car etc.

I worked around it - used an external firewire and a copy of another gray install disc. Did a flat install of that disc onto the firewire drive on another mac pro (new model that accepted the gray disc). Then bounced that flat install back to the HD on my mac pro. Seems to have done the job. Still don't know WHY this has happened but it's running a charm now.

Sound's like the optical drive (CD/DVD) needs to be cleaned. All it takes is a speck of dust on the lens to kill a read.

You can pick up a drive cleaner anywhere, but I have found the easiest thing to do is blow it with canned air.

Yup, sounds like the optical drive, if cleaning does not work, it may be time to pick up a new drive. at least they are fairly cheap - go for a recent Pioneer drive.

Lens Cleaners are dirt cheap, basically an audio CD with some test sound files that has little microfiber brushes on the bottom to clean the lens. Works wonders for computers/DVD/CD Players/any type of optical media. In the case that it doesn't work, like aquamac suggested, a Pioneer drive would be a good replacement since AFAIK those are the drives used in many official Apple computers.

You could try apples website to see if there is a firmware update for the optical drive if cleaning doesn't help