When I press "reply to e-mail", the sender's address does not appear in the "send to" box. Nor does it like being entered manually, and cannot auto-complete from contacts. I also get this notification:

Webpage error details

User Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; MS-RTC EA 2; .NET CLR 1.1.4322)
Timestamp: Sat, 29 Sep 2012 21:49:19 UTC

Message: 'ContactPickerCore.searchIndex' is null or not an object
Line: 1
Char: 100756
Code: 0
URI: http://gfx3.hotmail.com/mail/16.2.7056.0906/c2a.ie.js