I just spent a bazillion hours reinstalling P3D and various add ons.  I installed the C208 patch as well.  

 

On my previous P3D and C208 install it worked fine for months.  Now, I have this problem with the cockpit being transparent:

 

 

I tried deleting the P3D shader directory, but it did not help.  

 

Any ideas?

I installed one of the simconnects and it fixed the problem...

Which simconnect did you install? I'm having the same problem, and can't fix it for the life of me. From what I can tell, simconnect is automatically installed with SP2, and or Acceleration, right? Both of which I've installed and reinstalled multiple times hoping it would fix it. No luck, though.

Ah, nm, just went back and saw you're on P3D. 

Turned out to be fsuipc - worked after a reinstall of it.