It shouldn't change other contact's names to ther e-mails. What Windows, Messenger and Plus version are you using?
Did you try disabling and re-enabling custom names? Go to Plus! > Preferences > Contact List > Custom Names, uncheck 'Display custom contact names (enables "view by email")', click apply, check it again and click OK. Try restarting Messenger too.
Renaming Contacts - by BMKane on 10-31-2004 at 12:39 AM RE: Renaming Contacts - by marissa on 10-31-2004 at 01:51 AM RE: Renaming Contacts - by lopardo on 10-31-2004 at 02:05 AM RE: Renaming Contacts - by BMKane on 10-31-2004 at 03:12 AM
/ 
![[Image: userbar452797dd.gif]](http://img218.imageshack.us/img218/216/userbar452797dd.gif)
