When you have Cached Exchange Mode enabled, Outlook by will by default cache the main Global Address List as well.
This is called the Offline Address Book and is being generated on the Exchange server.
The command for the manual update procedure can be found here: Outlook will automatically download updates only unless the size of the changes is larger than 12.5% (one-eighth) of the total OAB size.
In that case the whole OAB is being downloaded again.
This means that in the worst possible scenario, an update to the Address Book won’t become available to the user until 48 hours after the change.
This situation however is extremely rare since the default maintenance time on Exchange is at AM and updates and downloads are usually performed during working hours.
Use Cached Exchange Mode but without OABTo always work with the Online Address Book, even when you have Cached Exchange Mode enabled, you can set the following Registry key and value.
This morning I was asked to update the Global Address List and Offline Address Book in an Exchange environment.
You could wait for Exchange to do it automatically (the default schedule is once a day) but what when you want to force the update to take place right now?