Make sure you have .NET Framework 2.0 installed and working properly.

 

If the above doesn't work, have you tried reinstalling it?

Just used the latest version earlier today, worked fine.

 

I`ve already got netframework 4.7.5 installed.

I`ve tried to reinstall occt as well as starting it from the unzipped folder.
Both hasn`t worked.

 

.NET Framework 2.0, 3.0, 4.0 and other are all different packages and higher version does NOT include older.

 

No improvement at all. I`ve switched form 4.5.7 to 3.5 and finally to 2.0, nothing changed same error message, as before.

Any other suggestions ?

 

I got it solved.
Simply, recovered my last Veeam Agent backup.
Occt works as before.