If Exchange 5.5 users start showing negative or otherwise nonsensical values for the inbox message count, the private information store is probably corrupt. This is a serious problem, and requires the use of the ISINTEG tool.
ISINTEG is a command-line utility that scans an offline information store and repairs any problems that are flagged with it. To run it, use this syntax:
ISINTEG [-pri]/[-pub] [-fix] [-l <logfile>]
-pri checks the private information store (the default option); -pub checks the public store. You must choose one or the other; you cannot use both options.
-fix repairs the information store if any problems are detected.
-l logs the results to a file of your choice.
Note that when you run ISINTEG, the Exchange service must be stopped and all mailboxes taken offline before it can enact any repairs.
For full details on the ISINTEG utility and what it does, you can read the documentation included with the Exchange Server 5.5 CD, at ServerSupportUtilsIsinteg.rtf.
Serdar Yegulalp is the editor of the Windows 2000 Power Users Newsletter.