Updating the global address list
Probably the first time for many months where the problem has been genuinely the GAL, rather than the OAB.
You need to start looking at your domain controllers.
Apparently this caused Outlook to delite the list of cached email adresses?? If you login to OWA you will see the GAL - that uses live information.
Therefore this is really 2 questions: 1) Why does the GAL not updating? Therefore the first thing you need to do is check whether changes to user accounts are seen through OWA. Go to Organization Configuration, and then click Mailbox. Right click the appropriate database and go to Properties 4. First of all I dont see any entries in the ewent viewer what so ever regarding any issues related to OAB or a like.
I made the changes in exchange server management console, and the changes stuck on the exchange server itself.Choosing the option to Download the Address book should have had no effect on the nickname files. If I access Outlook 2010 I see the full internal address list (GAL??I have never seen the entries lost by doing what you posted. All Users is the live information, therefore if you aren't seeing the information elsewhere, then the OAB isn't updating correctly. ) except that this is not updated and missing newly created users.I would also ensure that permission inheritance is enabled on every user account.Until you can see all of the information in OWA, don't think anything is going to change on the clients.