Sorry for the confusion ...
There was no single gpgol-File for deletion.
There were 100.000 other files from other programs.
No idea, why this has interferred with gpgol, but it obviously has.

I had a look into my \AppData\Local\Temp and found some 10,000 Files/Folders (nearly 100,000 files in total) with over 10 GB.
After deleting most of them, GPG4WIN 4.0.3 is working!

... Logging active, standard, with email content and meta information

I have produced a log using 4.0.3.
See attached.

Please find the requested log attached.
I don't know, where to look for such a file (candidate).

Thank's Diedrichs for this hint.
Here it works again using Gpg4win V.3.1.15.

No, unfortunatelly problem is still existing.

Any idea? Any update?

I had already tried both, to deselct all other add-ins and to select all possible add-ins.
No change of the behaviour.