The reason is Offline Address Book not being updated. By default, Exchange generates the Offline Address Book once a day at 5AM.
Besides, an Outlook 2007 client picks up the GAL entries using web distribution from the web based oab virtual directory. The OAB data is delivered to the directory every 8 hours by default.
To change this to 30 minutes, for example, use the following command:
Get-OABVirtualDirectory | Set-OabVirtualDirectory -PollInterval 30
To force a complete OAB update, you can use the following commands:
get-offlineaddressbook | update-offlineaddressbook
update-filedistributionservice %CAS server name%
Run the update-filedistributionservice command for each CAS server.
Of course Outlook 2007 cached-mode users still have to download the OAB again if they want the new information or simply wait 24 hours for it to happen automatically.
– On the client go to Outlook 2003/2007 | Tools | Send/Receive | Download Address Book….
– Uncheck Download changes since last Send/Receive
– Make sure Download Full Details is checked
– Click OK, wait for the download to complete (depending on your bandwidth and size of OAL, this may be close to instant, or it may take a few minutes)
– Check if the user appears in the GAL