Word opens wrong email client

I have Outlook for work and Pegasus Mail for not work. I like Pegasus mail, but when logged into my work account I want Word to call Outlook when I choose to ‘Share’ a document. Outlook is set as the default mail App in Windows defaults. Word calls Pegasus nonetheless.

(Is it just me or does the Pegasus Mail logo look rather like it might be a Steve Miller Band album cover?)

Files of extension .eml, .vcs, .oft, .ics, .hol are associated with Outlook. Nothing  in the extensions list is associated with pmail, Pegasus, WSENDTO or even anything that looks like an intermediary. In Settings, I can find ‘default applications by protocol’, and Outlook is already associated with MAILTO and FEEDS, but not OUTLOOKMAIL, which points at Windows Mail. Nothing points to anything like pmail, Pegasus, WSENDTO or even anything that looks like an intermediary. If I go to ‘Set defaults by app’ … I see Outlook is already associated with everything relevant; Pegasus is associated with literally nothing. And … Word still opens Pegasus. I can only assume there’s a setting in the registry that the Settings interface is not finding. It could be that Pegasus, which has been around a long time, is writing something to the registry that the more modern configuration tools no longer look for, but which Word still hooks into.

OK, let’s look in the registry. A quick search finds a few relevant keys occupied by Pegasus Mail or one of its helper programs:

• Computer\HKEY_CLASSES_ROOT\WSendToURL\shell\open\command
• Computer\HKEY_CURRENT_USER\SOFTWARE\Classes\Local Settings\Software\Microsoft\Windows\Shell\MuiCache

But these don’t matter; they are just Windows telling itself that Pegasus Mail exists, so they won’t be the problem.. What about:

1. Computer\HKEY_CURRENT_USER\SOFTWARE\Classes\mailto\DefaultIcon (current value: C:\MAIL\Programs\WSENDTO.EXE,0)
2. Computer\HKEY_CURRENT_USER\SOFTWARE\Classes\mailto (current value: “C:\PMAIL\Programs\WSENDTO.EXE” %1)
3. Computer\HKEY_CURRENT_USER\SOFTWARE\Clients\Mail (current value: Pegasus Mail)

Let’s look at these 3 keys. Naively, I can make them all point to what I hope are the analogous binaries/entries for Outlook, so I changed the key contents to:

1. “C:\Program Files\Microsoft Office\root\Office16\OUTLOOK.EXE”,0
2. “C:\Program Files\Microsoft Office\root\Office16\OUTLOOK.EXE” %1
3. Outlook

And now it works. I can say it did not work after changing just the first 2, and I do not know if it was only the third one, or all 3 that made the difference, but now Share from Word opens Outlook.Whether I’ve introduced some other error, I guess I’ll find out over time.

These are all keys for the ‘current user’, so I hope they won’t have a global effect! I’m never sure with Windows…

Look out, Pegasus!