Hello,
I'm using outlook 2007. Two days ago, we've enabled auto-archiving, maybe that't the source of our problems, but I still have to investigate.
At any rate, auto completion of email addresses in the to/cc/bcc fields has become a stopper, taking up to a minute to do something.
I've searched the web, but found only references to problems with McAfee which I don't have installed (http://www.groovypost.com/howto/microsoft/outlook/fix-slow-outlook-email-address-auto-complete/)
Thanks
Holger