Default global address list not updating 2016
Renaming just a single or some of the files will result in an OAB corruption. A benefit of manually deleting the oab-file is that before they are being re-downloaded, you are working with the Online Address Book.
When you find things working correctly for you now but not anymore after the oab-file were redownloaded, you know that the issue is with the oab-files on the server and not on the client or the Address Book configuration in general.
When the value is set to 0, Outlook will use 16 to prevent a “divide by 0” error.
This is called the Offline Address Book and is being generated on the Exchange server.
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.
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.In general, Outlook will automatically update the Offline Address Book (OAB) for Exchange accounts once every 24 hours.