My default P3Dv4.5 F-35A shows the interior, as if the model wasn't ported over correctly. Why doesnt yours?
Nasty.
Looks like either a corrupt set of textures (the obvious) or perhaps a missing Xml.dll file, something I've had a similar hassle with on some Carenado aircraft.
If you moved them direct from P3D3 to P3D4 that might be the cause. Maybe.
@Sundog
No, I was commenting on the default P3Dv4 F-35, not Dino's later payware model. I would have thought that L/M would have ensured it was usable in their current version of their sim, but apparently its not so.
Thanks though.