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.
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.
Key: All Users or any other object type such as All Contacts, All Groups or All Rooms.
Full OAB download threshold To modify the threshold at which Outlook will download the full OAB rather than the incremental update, you can set the following Registry value Key: As the value, set at which relative size a full OAB download should take place rather than an incremental update.
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.
Due to various synching schedules, it can take up to 48 hours before you could actually see a change in Outlook after a modification has been made on the Exchange server or in Active Directory.
In this guide, the relevant timings are explained and instructions are given in how you can directly force an update and resync, which can be very handy when troubleshooting or when you work in an Exchange environment which sees a lot of user mailbox mutations.
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.