It´s just the Cubase that crashes. Everything else works fine. Only thing that has changed since the crashing started is the new Mac Pro with the USB 3.0 ports and also one thing to mention is that I use the Apogee Symphony IO now with USB connection. I use to have it with PCIe connection. I´m waiting for the Thunderbridge for the Apogee though. Oh and I´m also using now two FireWire UAD-2 Satellite cards with Thunderbolt adapters as before I had two Octo PCIe cards inside the old Mac Pro. Waiting to get a PCIe Thunderbolt chassis for those cards. Those are the only things that have changed in my system. I used to have a plenty of crashes before, but they happened always when closing a project, never when trying to open up a project.
So maybe it´s one of these things… who knows…