As per Microsoft: "The problem occurs when WMI cannot use DCOM correctly because the System and Interactive accounts are being removed from the access control entries of the Default Access Permissions section of Dcomcnfg.exe. This behavior may occur when a user on the server specifically adds user accounts to the list (for example, the user may add the IWAM account). Adding user accounts removes the implicit entries for the System and Interactive accounts". See ME811321
for further details.
From a newsgroup post: "There are a few reasons for this problem to occur, but the most common is due to messages getting stuck in the Temp Tables within the mailbox store. A great utility allows you to remove the messages from those tables safely. Hope this works for you. If not, please contact PSS, as there are some other possibilities for this issue.
Please be advised that when clearing TEMPTable#1 you will clear any messages that are currently going in or out of the store. I would suggest performing this cleanup during off-peak hours, or when you know the users are not sending/receiving mail.
Steps using Mfcmapi v18.104.22.168 to clear the temp tables in Exchange 2000:
1. Double click on the Mfcmapi executable.
2. Click OK to close the "About Mfcmapi" window.
3. Click the "Session" menu and choose "Logon and Display Stores".
4. Choose the Mapi Profile, and then click OK. Note this can be a Mapi profile for the Administrators mailbox.
5. Highlight Private Folders. Note the name may change to SMTP (<Server
Name> (GUID)) when you highlight it. This is normal.
6. On the MDB menu, choose "Get Mailbox Table...". Note if there are a large number of users on the system, you may get a dialog box stating that the threshold has been reached. Simply close this window.
7. Double click on the SMTP (<Server Name> (GUID)) mailbox.
8. Expand the "Root Container" object and then highlight the TempTable#1 object.
9. On the Actions menu, choose "Delete Folder".
10. On the "Delete Selected Folder" window, place a check beside "Hard Deletion" and then click "OK".
11. To confirm that the Temp Table folder was deleted, choose "Refresh View" from the "Hierarchy Table" menu. When you expand "Root Container”, the TempTable#1 object should not be there.
12. Restart the IIS Admin service. This will rebuild the TempTable#1 object".