I have not worked with any of the processes and UNC paths. It should work if the networked folder is mapped to a Windows drive letter.

It was not necessary, nor desirable, to remove sections of code relating to passwords as this was part of the error trapping. You can enter your common password at the start of the sub in the updated version from my web site in the line 
Const sDefaultPassword As String = "#test#" 'Change as                      required
Use the test macro to test the process. If that works, then provided your rule identifies the messages correctly it will only process those messages on arrival.

You can remove the alternative Private Sub UnZipFile(vFname As Variant) as this is just included for completeness and is not required by the process.

Unless the user has a valid certificate correctly installed and used to sign the project it will not work correctly. My web page has instructions.