Unable to open project "A serious error has occurred"


I’ve had this a few times, but now my project will not open properly. It just finishes opening, but before I can click anywhere in the GUI I get the “A serious error…” cascading until I CTRL-ALT-DEL and kill the app.

Cubase 9.5.20
Windows 10 1709

Any tips, I really want to open my project!
It is creating small crash dump files in Documents/Steinberg/CrashDumps

Just an update - I’ve just upgraded to and it has the same issue :frowning: