I had the same thing happen to me about 2 years ago. After all my research, and work I wound up having to delete and recreate the users, of course it’s not quite that simple and I would start with one. If it works for the one then continue with the others.
<b>Please read the entire message prior to making any changes. I think I have all the steps.</b>
However I can NOT say that is a complete checklist of things to do, and can not be held liable should you decide to undertake this task.
1. Check existing settings for user on server and on local machine.
a. Make sure nothing has changed for the users at the server level for the domain or exchange.
b. Make sure the users are not in offline mode. If you are running in exchange cached mode, I have seen where Outlook did not “detect” the server as online after a loss in communication.
c. Check the individual send / receive settings in Outlook.
<b>2. If all else fails Delete the User and Recreate it.</b>
a. Back up users mail. Export it from Outlook is the safest way. If you are running in exchange cached mode the server could overwrite all the mail with blank.
b. Make note of any specific settings like security privileges, memberships, shares and so on.
c. Delete the user from the domain and recreate the user with the same ID or a different one if necessary. I was able to reuse the same IDs.
d. Grant all specific settings noted in step 2a.
e. Log the user off the workstation and log back in with the new ID and Password. ( This will create a new profile on the local machine because the recreated user is seen as a brand new user. )
f. Log off the “new” user log on with administrative priviliges and set up any specific local settings for the “new” user.
<b>3. Reassign the “old” profile to the “new” user.</b>
a. Right Click My Computer
d. Under User Profiles section click settings
e. Highlight the “old” user and click the copy to button
f. Click browse and select the “new” user folder under Documents and settings.
g. Click OK
h. Click the permitted to use button and type domain name”new” user or “new” user@domain
i. Click OK
j. Click OK
k. Click the warning message to allow the process to continue
l. Once complete, the time varies on the size of the users profile, it can take a while, Log off and log back on as the “new” user.
<b>4. Setup prefs and test.</b>
a. If needed, set up new mail prefs
c. If problem is resolved, import mail exported earlier.
d. Depending on space you may delete the old User Profile, <b>Only after you are sure the user has everything they had before.</b>