First of all, thank you very much.
I have 3 executables at hand:
WinSCP_5.13.3.exe
WinSCP20180622.exe
WinSCP20180627.exe
I attached
WinSCP_5.13.3.exe
to my taskbar not starting my workspace automatically, so it did not produce an error whenever I closed a file in the editor. It was such a relief which showed me which amount of stress the error had put on me before.
WinSCP20180622.exe
seemed to have the same problem, i.e. produce this error when automatically opening the workspace.
WinSCP20180627.exe
does not show this error anymore.
Is there a switch to turn off tracing in this debug version?
PS: Now the last problem I have is adding a shortcut to the taskbar which automatically opens my preferred workspace.
I tried different scenarios (... omitted ...) -- I found the solution (simple and logical indeed):
https://www.digitalcitizen.life/shortcut-arguments-parameters-windows/
Well, I think I knew this before but had forgotten about it. Just for the record, if anybody reads this.