windows mail keeps the email in 2 ways
in the folder C:\Users\user\AppData\Local\Microsoft\Windows Mail (change
user for what your name is
there is a file called WindowsMail.MSMessageStore
also there are individual files in the folder
C:\Users\user\AppData\Local\Microsoft\Windows Mail\Local Folders
with windows mail not running if you delete the WindowsMail.MSMessageStore
then goto "C:\Users\user\AppData\Local\Microsoft\Windows Mail\Local Folders"
and delete the offending email when you restart window mail it will rebuild
the WindowsMail.MSMessageStore
there nay be more than one WindowsMail.MSMessageStore file
this worked for me when I had emails stuck in my outbox what I think happens
is if you force windows mail to shut the db file becomes corrupt
if you are not sure rename the WindowsMail.MSMessageStore files and delete
the offending files from
"C:\Users\user\AppData\Local\Microsoft\Windows Mail\Local Folders"