I had numerous unused SMTP servers in my Apple Mail list, so I decided to tidy up and found the following steps do it (yeah!):
- Access the Finder menu and navigate to Go to Folder and type /Library/Scripts/Mail Scripts/.
- Look for Manage SMTP Servers.scpt and open it. (This should open the Script Editor.)
- Hit the Run button, then select the (SMTP) servers you want removed.
- Hit OK and a message stating the deletion was successful should pop up.
That’s it, now when you go back to Apple Mail you’ll see a nice, pruned list. BTW, you will only be able to delete SMTP servers that are NOT in use by any of your mail accounts.