The plan is marked for IFR via jetways. Started at runway.
If I open the built in ATC it gives me VFR choices. Depart straight out etc.
I takeoff, engage the AP and change ATC to local Departure. Offered choices of opening IFR plan or Copy IFR Clearance etc.
If I try to change to IFR via either method, P3D crashes..."P3D is not responding."

Suggestions welcomed.

I don't use P3Ds built-in flight planner.  Just like in previous versions it is still full of bugs and very slow.

Use Simbrief, or another freeware flight planner that exports to P3D format like Little Navmap, put it in the P3Dv6 files folder in C:/Users/your name/Documents, and load it up in the P3D flight planner.

Dave