The Mailbox Resources tab, under the properties of the Private Information Store object in Exchange, may report having items in the store when the client sees nothing but empty folders. Sometimes this appears as objects with unfamiliar names such as Admin or Internet Mail Services. This can also cause incorrect reporting of the size of the information store.
Here's why this happens. Exchange creates several mailboxes for its own internal use. Exchange does not maintain internal performance counters (such as size) for these objects, and they're not reported to clients for obvious reasons -- since they're not client mailboxes but internal objects, and accurate statistics are not maintained on them continuously. The messages used by these internal objects are sent to and from connectors (such as the connector for the Internet Mail Service or Lotus Notes) as part of the message delivery system, so all of their actions can be logged. Some Exchange Server connectors talk directly to the Message Transfer Agent and don't use these internal objects, such as the X.400 connection.
To repair problems with the mailbox resources, you'll need to run the ISINTEG utility, a command-line utility provided with Exchange which checks the integrity of the mailbox system. Use the following command line:
ISINTEG -FIX -PRI -TEST MAILBOX
A full description of ISINTEG's functions can be found in a document named Isinteg.Rtf, on the Microsoft Exchange Server 5.5 CD in the Server\Support\Utils directory.
Serdar Yegulalp is the editor of the Windows 2000 Power Users Newsletter.