Why does my global address book take up to a day to update when adding or removing users?

Solution 1:

My guess is that your users are operating in cached mode when connecting to Exchange. If that is the case, they are probably downloading the offline address book. This is generated on a schedule and then updated by the clients on a regular basis.

You may want to alter the default schedule to meet your business needs (the frequency of changes, the size of the address list, etc.).

A good article that explains how to work with the offline address books is found at http://www.msexchange.org/tutorials/Offline-Address-Book-Best-Practice.html.

Of course, it could be that my guess is wrong and this is not what you are experiencing, but without more information, this at least gives you a possible answer.

Solution 2:

I think you want to look at rebuilding the Recipient Update Service (domain and/or Enterprise) if you desire to see the changes the same day. My understanding is that this is rebuilt nightly as part of the exchange maintenance, but you can force it to run manually.

http://www.msexchange.org/tutorials/MF017.html