Information Store stops unexpectedly and cannot be repaired

The information store stops unexpectedly and you are not able to restart it. An error message similar to the following may be displayed when you attempt to restart the information store: If you do not have a backup of the information store and circular logging is enabled for the information store database files, it may appear that you cannot repair the information store so that you can restart it.

Before you perform the following steps, perform an offline backup of the Exchange Server databases and log files. In addition, you may want to set up an Exchange Server computer to recover information from the directory service contained in the Dir.edb file. For additional information about setting up a disaster recovery Exchange Server computer, click the article number below to view the article in the Microsoft Knowledge Base: To repair the information store when you do not have a backup and circular logging is enabled:

1. Use the Chkdsk.exe program with the /f switch to fix any errors on your hard disks. To do so, at a command prompt, type chkdsk /f drive, where drive is the hard disk you want to check, and then press ENTER. For example, to fix any errors on drive C, at a command prompt, type chkdsk /f c:, and then press ENTER.
2. Remove the log files for the information store by moving them to a different folder, and then start the information store. The log files are Edb.log and Edbxxxxx.log, where xxxxx is a series of hexadecimal digits (for example, Edb00001.log). The log files for the information store are typically located in the Exchsrvr\Mdbdata folder on the drive that Exchange Server is installed on.
   
   If the Information Store does not start, and an error message similar to the following is displayed when you attempt to start the information store, you must copy the log files back to the folder where they were originally located, and then proceed to step 3:
   Server specific error 4294966746 (or error -550, �JET_errDatabaseInconsistent�).
3. Use the Eseutil.exe utility with the /r switch to recover the Exchange Server databases. If a -1018 error (JET_errReadVerifyFailure) is returned, proceed to step 4.
4. Use the Eseutil.exe utility with the /mh switch to check the consistency of the public and private information stores. To do so, type the following commands at a command prompt, pressing ENTER after each command:
   eseutil /mh path\pub.edb
   eseutil /mh path\priv.edb
   where path is the location of the information store database files. For example, if the database files are located in the Exchsrvr\Mdbdata folder on drive C, type the following commands:
   eseutil /mh c:\exchsrvr\mdbdata\pub.edb
   eseutil /mh c:\exchsrvr\mdbdata\priv.edb
   If the Eseutil.exe utility indicates that either database is not consistent, proceed to step five and run the repair operations against only the databases that are inconsistent.
   
   CAUTION: Repairs to the database using the eseutil /p switch, deletes pages (increments the repair count) and the database is not stable and reliable after that.
   
   The following are symptoms that can occur if you use the repaired database in production:
   
   
   • The information store either does not stop or stops responding.
   • The information store stops accepting mail from the message transfer agent (MTA).
   • E-mail remains in the Outboxes of the users.
   • The Store.exe program runs with very high CPU use with no load on the server.
   • The Store.exe program generates an access violation if there is a heavy load.
   • Users cannot open e-mail attachments or e-mail messages.
   If you have to run a hard repair (eseutil /p) on your production database, Microsoft recommends that you perform an offline defragmentation (esutil /d) and an integrity check (isinteg -fix) to make sure that the database is stable after the repair procedure.
   For more information about using the eseutil /p switch, click the following article number to view the article in the Microsoft Knowledge Base:
   259851� Ramifications of running the eseutil /p or edbutil /d /r command in Exchange
5. Use the Eseutil.exe utility and the Microsoft Exchange Information Store Integrity Checker (Isinteg.exe) to repair, defragment, and check the integrity of the public and private information stores:
   
   NOTE: If from the previous step (step four), either of the databases are inconsistent, then the repair operation, eseutil /p, should only be run against the database that is inconsistent.
   1. At a command prompt, type eseutil /p /ispriv, and then press ENTER.
   2. If log files for the information store exist, remove the files by moving them to a different folder. For more information about the log files, see step 2.
   3. At a command prompt, type eseutil /d /ispriv, and then press ENTER.
   4. At a command prompt, type isinteg -pri -fix -test alltests, press ENTER, type y when you are prompted to do so, and then press ENTER again. Repeat this step until no warnings, errors, or fixes are reported.
   5. At a command prompt, type eseutil /p /ispub, and then press ENTER.
   6. If log files for the information store exist, remove them by moving them to a different folder. For more information about the log files, see step 2.
   7. At a command prompt, type eseutil /d /ispub, and then press ENTER.
   8. At a command prompt, type isinteg -pub -fix -test alltests, press ENTER, type y when you are prompted to do so, and then press ENTER again. Repeat this step until no warnings, errors, or fixes are reported.
6. Start the information store. If it starts successfully, perform the following additional steps:
   1. Disable circular logging for the information store database files.
   2. Run Performance Optimizer.
   3. Verify that e-mail clients can connect to the Exchange Server computer.
   4. Perform an online backup of the server.

When circular logging is enabled, the server automatically overwrites the oldest transaction log files after the information they contain has been committed to the database. This reduces the amount of disk space required to store the log files, but it prevents you from performing differential and incremental backups, and it may also prevent you from using the log files to repair a damaged database. Circular logging is enabled by default.