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My Mac Pro ( late 2009 custom assembled in Ireland by Apple)
- Processor Name: 3.32GHz Quad-Core Intel Xeon
- Memory: 32 GB
- Processor Interconnect Speed: 6.4 GT/s
- Boot ROM Version: MP41.0081.B07
- NVIDIA GeForce GTX 680
- VRAM (Total): 4096 MB
came originally with Snow Leopard. I still have the original DVD in mind conditions and the DVD disk reader (very seldom used) works perfectly
After I upgraded to El Capitan, I am totally unable to reinstall Snow Leopard in any of the additional disk slots in the machine.
I removed all the hard drives, bought a new 1 TB Seagate drive and installed it in bay 1.
The computer boots with Snow Leopard and allows installation, however after the message telling me the install was successful the Mac doesn't boot - an error message tells me the software is not meant for my particular machine. I tried every kind of keyboards combos I am aware of.
People at the local Apple store told me that I will never be able to go back to Snow Leopard as after Yosemite the system patches the computer ROM making the downgrade impossible.
But I do need Snow Leopard as I have a number of PowerPC apps and files I need to use.
Any hints please?