Hey I know the answer to this question is... it is not supported but...

I just purchased a new Mac Pro to put a Software Only system on.  As I was trying to downgrade it to tiger I realized that the new Mac Pros cannot go back to Leopard.  Something I think Apple should post on their site but I am sure i could have figured it out somewhere if I looked harder.  Here is my problem we need to the system up and running Monday.  I have been running 2.8 on my Leopard System at home for many months but our tech guys are a nervous about installing a leopard system into a Unity when all the other computers are running Tiger.  Has anyone done this in the wild and have there been any issues?  I know Avid is right around the corner with Avid 3.0 and I even hear there are Late Betas out there.  I would hate to Return this computer with all its new Speed and Glory to buy a refurbished or used system only to have update like 2 days later, or more likey early June.  If anyone knows of any problems this could cause I will just find and older system but if anyone is actually doing this and it has not been an issue then I try and see if they want to try it.

We are also Running Unity 5.0.

Thanks for any thoughts.

I'm guessing this answer is coming too late for you, if in fact you needed to know by Monday.  But I'll fill in a few blanks for others who may have these same questions.

The Harpertown MacPros CAN run Tiger, you just can't use the Tiger install discs on them.  You have to install on a remote disc and put it into the MacPro, or start your MacPro in target mode and install from another computer.  HOWEVER, its hard to get a version of Tiger that has the necessary drivers for the display cards.  If you have an ATI 2600 card, you can use Tiger install discs for the 20" Aluminum iMac from last year.  It does work, but it might be a pain to get it going.  If you have NVIDIA cards, I don't think you will find Tiger drivers for those.

As for Leopard and Unity, that's not going to work.  When v3.0 is released, facilities are going to have to upgrade the File Managers to the latest versions along with their non-Leopard and Windows Vista clients.  Then, new (v5.1) client software is installed on the Leopard and Vista clients.  So, you're really talking about a facility-wide change that will have to happen before Leopoard will be supported.

Hopefully, you found some workaround.  Hopefully, you're only weeks away from getting this to work the way you want it to.

Thanks for the info.  Interesting about running Tiger on the HarperTown.  I was about to ship it back to Apple but now I might give that a try.

Did you succeed in getting Tiger to run on a MacPro acbrock?

Wait, have we checked that unity version?

I have 5 leopard clients (v5.1) editing on a 4.2.4 unity lanshare.

Is there not a small update that would let him roll that client on Leopard onto his Unity?

Check this before getting too deep into the Tiger backpedal

Unity Client 5.1 read me-->

Avid Unity MediaNetwork v5.1 client software can now be used in earlier MediaNetwork
environments. If you have a MediaNetwork v4.1.6 or v4.2.4 infrastructure running the
appropriate MediaNetwork server software, you can now run MediaNetwork v5.1 client
software on your Windows XP and Macintosh (10.4.11) clients. Windows Vista and
Macintosh Leopard (10.5.3 and later) clients with MediaNetwork v5.1 client software can
also be used in MediaNetwork v4.1.6 or v4.2.4 environments.

Keep digging...