13.All Prospects is in use and cannot be unapproved
I am struggling with the same issue and it is really annoying. Maggie, did you eventually figure it out and if yes, please share?
You don't need to unapprove it in order to edit it. Simply right click on the approved email and click "edit draft". When editing a draft version of the email template (or even an email), the approved version is still intact. Only until you actually approve the draft version, does it overwrite the approved version and place all of the emails based on that template back into draft mode. Until you approve those emails, the current/approved email will still be used. This is to give you a chance to review the draft versions and make sure the changes you made to the template didn't mess anything up on the approved emails.