History: We upgraded from Office 2003 Pro to Office 2007 Enterprise. Then the problems started. Outlook 2007 doesn't play nicely with others... meeting requests come in without the ability to accept/decline/forward or do any other action. Even with the junk mail filter turned off altogether, emails from senders whose email address and domain have been added to the safe list still get sucked into the junk mail folder, even though the only email account associated with this Outlook setup is in the same domain as those getting rejected (proprietary private domain for a business, not Yahoo/Hotmail/etc.). Followed all the Outlook 2007 troubleshooting steps we could find, but nothing solved the problems (possibly due to having to use IMAP -- UNIX mail server, lots of UNIX and Mac users as well as XP and Win7 in the same network, so MS Exchange server is out of the question). So, Outlook 2007 became a time-sucker in addition to its quirks of random hang-ups and crashes. All available Windows updates and Office updates had been applied, to no avail. (BTW - My cohort in this process is MS Gold certified network guru, so I'm not just hacking around solo here....)
Next logical step: go back to a known workable scenario = Outlook 2003. Research online indicated you can roll back Outlook 2007 to Outlook 2003 without messing up the rest of Office 2007. So, we uninstalled Outlook 2007, rebooted, deleted all instances of the mapisvc.inf files (since 2003 allegedly needs to create its own rather than use the 2007 version), installed Outlook 2003, rebooted again, started Outlook 2003 -- no dice: Outlook 2003 won't run other than in Safe Mode and still crashes frequently in safe mode. Researched a bit more, found indications that we should remove the HKEY associations for Outlook 12. Just to be safe, uninstalled all of Office 2007, uninstalled all of Office 2003, regedited the appropriate HKEYs, deleted all mapisvc.inf, rebooted, reinstalled only Office 2003, started Outlook 2003 and still no dice. Upgraded back to 2007, Outlook 2007 kept hanging up. Performed system restore to point preceding all the uninstall/reinstall processes, then uninstalled all of Office 2007. That's where we are now.
The goal is to get back up and running with Outlook 2003, by hook or crook. What have we missed?