Is there a way to completely reset the Mail app?
I had this issue on my Win 10 Desktop PC, and also with .132 update installed:
In the Mail app (setup with my IMAP email address) I can only view the Inbox. If I select another IMAP folder, such as Sent or Draft, it just sits there and freezes. I've removed the IMAP account (twice) and added it back, but still can only get it to view the Inbox folder. Other email programs, such as Thunderbird on the same PC, and Samsung Email on my Note can access all IMAP folders. Even the old Windows Live Mail on my Win 7 drive works fine.
Settings > Apps > Apps & features > Mail and Calendar > Advanced Options > Reset
-Eddie