I came across an article on an MSDN blog detailing a modification you can apply from within Windows XP or Vista in order to speed your Outlook start-up time. Navigate to C: > Users > Your Username > AppData > Local > Microsoft > Outlook on Windows Vista or C: > Documents and Settings > Your Username > Local Settings > Application Data > Microsoft > Outlook in Windows XP and rename your "extend.dat" file to "extend.old."
Outlook will essentially repair itself upon its next launch and recreate an extend.dat file – this should significantly reduce your start-up times.
Note, there’s no guarantee this will fix all types of slow start-up times for Outlook 2003 or 2007. There could be plenty of other causes including a limited amount of RAM, an abundantly large personal files folder (.PST) and/or a bloated or corrupted add-in.
Source: Sundara Prabu via MSDN Blogs
I run Outlook 2003 and synchronise with both a Treo PDA and Salesforce.com. A few reinstalls of the Outlook connector and I had tonnes of duplicated tasks, events, and contacts (the dupe events though because they were all in the past I had no idea of the extent of). The solution I found was an app called ‘Duplicate Killer’ from a bunch called 4team.biz. Essentially analyses and removes dupes on contacts, events, tasks. I know this is going to sound like a plug but it took me ages to find something like this and it has cut my Outlook startup time from 2 mins plus to about 30 secs … I suspect there are a lot of other people out there using stuff like Salesforce with Outlook and PDAs who are going to be experiencing similar problems.
Renamed extend.dat and restarted Outlook.
Worked like a champ!!
Thanks much.
XP and Outlook 2007