My goto touring system is an RME UFX — but I’m also on Mac.
I never heard of people having issues with the RME drivers that are rock solid. I use on an everyday basis two RME UCX on two different Windows setup without any issue. In both setup all the inputs and outputs of the UCX are perfectly recognized.
May of our users use RME products without issues. We have a few RME products that we test GP with and it all really works just fine.
Are you Windows 10 or Mac? If you are Windows 10, which RME ASIO driver exactly are you using?
Win 10 and this older driver…
I should try to find this driver and give it a try, although Jeff Petersen said to re-install 3.1.25 which I plan to do this evening. BTW, thanks for your help 
Thanks David. I have the same problem with the 1.168 driver. The problem is: GP doesn’t like it when I attach two Freface 800s together. So, for now, I have solved the problem by disconnecting the my extra FF800 and going with just one connected to Firewire and the computer. I will use my second FF800 offline and just route its output to an ADAT into the now single FF800. This works just fine and I can live with this and move on to bigger and better things … like making music
Thanks again for all your help.
I asked you what is you issue:
It was “GP to recognize that your Fireface 800 has more than two audio outputs”…
Now, it is that you still want to agglomerate two Fireface units which doesn’t work properly. So you confirm it works properly with only one Fireface 800?