I just upgraded from Gpg4Win 2.3.4 to version 3.0 and now I cannot sign or check signatures anymore. I use Win 7 (64bit) and after right-clicking in the file explorer I select "more GpgEX options" and then e.g. "Prüfen". As result I get this error:
So Kleopatra doesn't start.
With GPG4Win this Kleopatra starts fine.