If you use any of the Acrobat Pro applications you may have noticed new emails in Outlook have an annoying “Attach as Adobe PDF” button that just won’t go away. You can untick it via the View > Toolbar option in Outlook but as soon as you close and re-open Outlook, it’s back again.
To fix it, open regedit (Start > run > regedit) and navigate to HKEY_LOCAL_MACHINE > SOFTWARE > Microsoft > Office > Outlook > Addins > PDFMOutlook.PDFMOutlook.
Double click on “LoadBehaviour” and change the value to 0. (If you want to bring the button back again you can always change the value back to 3).
Next time you open Outlook it’ll be gone, until you install the next Acrobat update. Then you’ll need to go through this procedure again.
the procedure you outlined above did not work. Deleting the registry key from the left pane did though . . .