I need some help. I am running a really old piece of software for sign writing. Is there any way of running OS Snow Leopard on a Mac Pro 2013 Trash Can? It is designed for Snow Leopard which I had on a pre retina IMac. 2 of these machine have now broken down, so I want to go back to Mac Pro's I have 2 Trash cans running Mojave, so I do not have to go to cloud based Adobe products. Alternatively, I need to get OS Mojave to recognise a Sentinal Hasp Security Dongle that the software needs. The software loads onto Mojave but it cannot see the dongle. Can anyone help me?