I recently installed Office 2007. I have 2 POP mail accounts. Several times a day I get an icon in my tray saying "Microsoft Office Outlook is synchronizing folders" and everything pretty much locks up. I lose use of Outlook for up to half an hour, along with pretty much any other program open at the time.
I thought maybe it was a memory issue, so I upped my memory from 512 to 1 gig. No difference.
I read on another site that this refers to the box that is checked on the properties box for each folder that says "Automatically generate Microsoft Exchange views", so I went through EVERY folder, including contacts, calendar, etc., and unclicked it. I don't have an Exchange server.
I did have Intuit QuickBooks Customer Manager installed, but hadn't used it in over a year, so I uninstalled it, thinking it may be what was being synchronized.
That didn't help either.