XADM: Event ID 42, "The database engine found a bad page"

When you run Microsoft Exchange Server version 5.0, the server may receive the following event in the Windows NT Application Log of Event Viewer:

This event indicates that the internal structure of the database has been comprimised, as the database's internal references (pointers) are mis-aligned and/or corrupted. The server may become unusually slow, sluggish, or unresponsive.

This can result from replaying the incorrect transaction log files after a restore operation.

A JET_errBadPageLink error, or "bad page link," indicates logical corruption, not physical corruption. For further information regarding physical corruption in an Exchange Server Database, please refer to the following Microsoft Knowledge Base article:

To work around this problem, perform the following steps:

1. Restore the Exchange Server Database from most recent Full Online Backup:
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   • Restore the Exchange Server Database from the most recent Full Online Backup BEFORE the Event ID 42 started appearing in the Application Log of Event Viewer. NOTE: It is crucial that only the log files that are restored from tape get replayed, NOT any existing log files that may exist on the Exchange Server's hard drive.
   • After that is done, the customer can use the Microsoft Exchange Mailbox Merge (exmerge.exe) utility to export the users' data, then import it back into a new priv.edb file. This utility is included in the Microsoft BackOffice Resource Kit version 3.0
2. Use the "Move Mailbox" feature in the Exchange Administrator program to move users from the corrupt Exchange Server to another. Recreate the priv.edb file on the original server, then move the users back to the original server.
   
   CAUTION: The next series of steps contain information about using the Microsoft Exchange Database utility (edbutil.exe). Using it incorrectly can cause catastrophic problems. Before you run this utility, you should first make a backup copy of the database files. Microsoft cannot guarantee that problems resulting from the use of the utility can be solved. Use this tool at your own risk.
3. Attempt to run EDBUTIL /D (Offline Defrag)
   
   This may remove the bad page link (if the bad page link resides in an unused portion of the database). Make sure you have a backup of the Exchange Server Database before you begin.
4. Attempt to run EDBUTIL /D /R (Repair)
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   • This will forcefully remove the bad page link from the Exchange Server Database. Make sure you have a backup of the Exchange Server Database before you begin.
   • After EDBUTIL /D /R has finished successfully, try restarting the Information Store. If the Information Store starts, Microsoft highly recommends that Isinteg -fix be run against both the Private and Public Information Stores to resolve any inconsistencies that may have arisen as a result of running EDBUTIL /D /R.
     
     For additional information about Isinteg utility, please refer to the Troubleshooting section in Volume 2 of the Microsoft Exchange Administrator's Guide, or you can refer to Microsoft Knowledge Base article 182081, "XADM: Description of ISINTEG Utility."