Hello EdLe,
The issue might be caused by corrupt files that MSN uses to synchronize the e-mails from the hotmail servers. Follow the steps below to fix the issue:
For Windows XP:
http://answers.msn.com/thread.aspx?threadid=bc389939-759e-4d79-b9e5-304fe757b8f7
For Windows Vista/7:
http://answers.msn.com/thread.aspx?postid=293bbff5-1e7b-4ac5-921b-232d1a48479a#293bbff5-1e7b-4ac5-921b-232d1a48479a
Thanks
Shawns