My Windows Live Mail stopped working for certain email accounts.  Error Msg: 0X800CCC90 (can't retrieve or send emails).  I went through the suggested trouble shooting measures - none worked.  Several forum experts suggested to export (backup) emails a non-working account, remove the account, then reconfigure it.  I did all that (being careful to note the existing configuration that has worked for years until this Error Message appeared).  I copied the configuration exactly when I re-configured the account.

When I tried to import the emails, a message came back there were no messages to be found!  I checked the backup file properties:  the file had only 18 bytes!!

What the heck happened?  How can I retrieve these lost messages?