Background: On any Outlook client, the Offline Address Book (OAB) is used when pulling the list of Outlook Contacts in order to address a message. The offline address book is only updated once every 24 hours, however the update can be forced by (send/receive, download offline address book). To add more to the story, the Outlook Name Cache is a function of Outlook in which the “To:” line of a new email will automatically populate as soon as the user inputs the first letter of a recipient that they have previously communicated with. The Outlook Name Cache is stored in an .N2K file stored in the users local profile.
Note: Outlook ‘cached mode’ OST file is not related to the offline address book or outlook name cache.
Here are the initial steps to troubleshoot the dreaded “we added a new user or changed a users name but people aren’t seeing it”. These steps will help update the address book sooner:
1) Run Update-GlobalAddressList “Default Global Address List” from the Exchange Management Shell of the exchange server. This updates the address list on the server. Note: You may have to wait awhile for this step to take effect.
2) On the desktop outlook: (send/receive, download offline address book).
3) Further diagnosis if the above doesn’t work: open Outlook Web Access (OWA) and see if the address is there or has been updated. OWA is the best way to troubleshoot most exchange issues because it eliminates the variable of the Outlook client. If OWA looks correct, then we know the server has the proper information and the issue is on the client side (Outlook client), however, if OWA is wrong then it’s a Server issue and the server does not have updated information.
4) Confirm AD replication, from command prompt of your DC’s run “repadmin /showreps” and “dcdiag”. See troubleshooting AD issues.
Troubleshooting the Outlook Name Cache: to further complicate things there is the Outlook Name Cache (autocomplete). This can in rare cases get bad information in it, a new outlook profile will give a completely new outlook name cache. Or to delete one bad entry from it, start typing the name, let it auto-fill, then hit the delete key on the keyboard when the autofill address is show in the To bar. This can be helpful if an Outlook user’s messages are bouncing back when they send to a specific Exchange user (this can happen after certain types of migrations if X400 was not updated) or in rare cases a user outside the company.
How to properly rename an AD / Exchange user: If you ever need to rename a user, the proper way to do it is right click their account in active directory users and computers and click “rename”. There are a bunch of different fields involved, and this way it will change them all. Open the user in AD Users and Computers to make sure their Display Name, First and Last Name fields are correct.
If you only want to change a users email addresses then you can do that from the recipients node of the Exchange Management Console. In this case I would go in and verify their old email address and new one are present, if this is a last name change situation.