FYI, I just upgraded my MacPro1,1 from Snow Leopard to El Capitan (very non-trivial requiring a custom boot file.)  I wanted to run a bunch of music software that never got past PPC, so I needed to keep Snow Leopard around. It turns out the easiest solution is to buy Snow Leopard server from Apple.  Parellels and Fusion allow it to be virtualized, and it can still be purchased new from Apple for $20.  Because I bought it right around Black Friday, I got it with free two day shipping.  You have to call them as its not on the online store, and it helps to know the part number, but it&#x27;s still for sale.