Publisher 4.0.1 throws the error ApiResultCodeUNEXPECTED_EXCEPTION
The main issue is that the installer does not properly remove the previous verion of publisher before installing.
To remove Publisher manually:
Go into Control Panel/Programs/Programs and Features/Uninstall a Programs and uninstall Retain Publisher
Go into File Explorer and type into the address bar %APPDATA% go into the Gwava folder and delete the Retain Publisher folder.
Now you can install the latest version of Retain Publisher which can be downloaded from the Retain web console under the Tools link at the top right corner of the screen.
related to bugs: