XADM: Restoring a Public Information Store from an Earlier Service Pack

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When an Exchange service pack is installed, the private and public information stores are updated to the current service pack. If you attempt to use a public or private store from an earlier service pack, the information store service will fail to start, and the error received will reflect that the store is the wrong version.

In case the only good backup is one from an earlier service pack, you can take steps to get the older information back without having to reinstall all of Exchange and each of the service packs. If only the public information store needs to be restored, perform the following procedure:

1. Determine which version of Exchange was running when the backup of the public information store was done.
2. In Control Panel, open Services, and stop the information store service.
3. Rename Mdbrest.dll to Mdbrest.xxx. It is located in the EXCHSRVR\BIN directory.
4. Copy the Mdbrest.dll from the SETUP\<platform>\BIN directory of the service pack that is the same as the version as the backed-up public information store.
5. Restore the public information store.
6. Rename Priv.edb to Priv.xxx in the EXCHSRVR\MDBDATA directory.
7. Run ISINTEG -PATCH. You will get a warning stating that the private information store was not found. That is expected because it was just renamed.
8. Start the information store service again.
9. Log on to the Exchange client as a mailbox that has rights to all the public folders. There will be no messages available from the private information store at this time, but all the messages and folders in the public information store will be available.
10. Move all the public folders into a personal folder file (*.pst file) from the client.
11. Shut down the client software, and then stop the information store service again.
12. Rename Pub.edb to Pub.xxx, and rename Priv.xxx back to Priv.edb (from step 6). These files are in the EXCHSRVR\MDBDATA directory.
13. Rename or delete Mdbrest.dll in the EXCHSRVR\BIN directory, and then rename Mdbrest.xxx to Mdbrest.dll (from step 3).
14. Run ISINTEG -PATCH. You will get a warning stating that the public information store was not found. That is expected because it was just renamed.
15. Start the information store service again.
16. Log on to the same Exchange client as in step 9, and move all the public folders from the personal folder file up to All Public Folders.

This procedure brings public folders from an earlier service pack and updates them to the latest service pack without your having to reinstall Exchange and all the service packs.