Question : New Exchange 2007 Mailbox not showing in GAL for Outlook, but does show in OWA

I have to assume this is a cached offline address book issue, because when adding a new user to our Microsoft Exchange 2007 environment they do not show up on the GAL for Outlook (running in cached Exchange mode). If I turn off cached mode or access mail from OWA, the new user DOES show in the GAL. The oddest part is a manually re-download of the address book using the Send/Receive button does not make any difference! This is seriously irritating my bosses as we add people to our business and they cannot contact them! Why would Outlook not download a new copy of the GAL when instructed to? This makes no sense!

Answer : New Exchange 2007 Mailbox not showing in GAL for Outlook, but does show in OWA

If you make frequent changes to the domain which need to be reflected in the GAL faster than the scheduled update time, then you can change the frequency that the offline address list is updated. While changing rebuild schedule for the OAB isn't recommended by Microsoft, but you may wish to make the change.

   1. In Exchange start ESM.
   2. Open Recipients, then Offline Address Lists.
   3. Right click on "Default Offline Address List" and choose "Properties".
   4. On the first tab, adjust the "Update Interval" to "Use Custom Schedule".
   5. Click on Customize.
   6. Select which hours you want the update to run. The frequency should depend on the size of your address book and how frequent the changes are made.
      A good suggestion would be to run the update three times a day - approx 6am to ensure that early starters get their updates - approx middy to catch any changes made in the morning - approx 6pm to catch any changes made during the afternoon.