Unwanted Folder in Outlook

Here's the fix:

1. On the phone, open the E-Mail app
2. Hit the Menu Key > Settings > General Settings
3. Select Spam Addresses and look for any errant email addresses, especially *@yourdomain.com entries, which would filter any messages from your domain.
4. Remove those addresses

Now the user can move the messages out of the Unwanted Folder and delete that folder, and email will stop being filtered improperly. 

NOTE:  If your device is connected to a corporate Exchange/Office 365 account, I would disable the SPAM filter on the phone completely, and let Exchange handle the spam filtering; since it seems that the built-in feature is more of a nuisance than helpful.