Thank you John,
it's all very strange.
I tried something in Montage Center last week.
Cannot remember particularly what I was doing but, the program either crashed or closed down normally, but now the program will not start.
It is a stand-alone program, so should run okay without TC loaded.
Which is normally the case.
It appears it is looking for something to load/open but cannot find it.
What this could be I have no idea.
Perhaps I'll just go back to using Adobe Premier pro.
You can design without engineering, but you cannot engineer without design.
Using Win 10 with Designer 2017-2020 and TurboCAD Pro. Plat. 2018-2020 + Lightworks (64-bit versions) + AnimationLab 5.2.
Windows 10 Pro (1909) 64-bit