How to decrypt an email when no internet connectivity is available

Mail Extensions in macOS Mail do not properly support offline mode. As a result this means without internet connectivity GPG Mail will not be able to decrypt and verify email messages.

To workaround this limitation, you can use GPG Services to decrypt an email when you are offline:

1. drag encrypted.asc attachment to desktop
   
2. double clicking the file will decrypt the file and save a new file to desktop called encrypted
   
3. right-click new file and select Get Info
   
4. add .eml as file suffix in the Name & Extension field and confirm with Enter
   
5. Finder will ask to add extension - confirm by clicking Add

You can double click the resulting eml file encrypted.eml to open the decrypted email message.