Database Unable to Mount while Restoring the Microsoft Exchange Database

Symptom

When I restore a Microsoft Exchange database, the database is unable to mount. The required logs are missing or the transaction logs are not contiguous. There are event errors such as 454, 455, and 2006 in the event log.

The following two reasons could cause the database mount failure:

Reason 1: The Purge Exchange log option is enabled in the UDP settings and this setting deletes the transaction logs after every backup. Then user try to restore previous session after several backup which purge log operation occur.

Reason 2: Users have manually deleted the transaction logs or the logs are deleted by other programs such as an antivirus software.

Solution

Solution 1: If you have enabled the Purge Exchange log option and the transaction logs are not contiguous, then restore all the sessions one by one, starting from the latest session, until the session fails to restore. If the latest session fails to restore, then try Solution 2.

Solution 2: If Solution 1 does not work, use Solution 2. This solution resolves both the issues.

For example, you want to restore the Test database from Session 1. The following steps use the database name as Test.

1. Log in to the Exchange server on which the database is located.
2. Delete all the files (such as *.edb, *.log, *.jrs, *.chk) from the database folder.
3. Mount the database to create an empty database.
Mount-Database –Identity Test
4. Restore the same session again to the original location.
5. If the restore is successful, you do not have to perform the following steps. If the restore fails, continue with the following steps.
5. Mount the database again.
Mount-Database –Identity Test
6. Create a temporary database.
new-mailboxdatabase –name OtherDatabase
7. Move the mailbox to any other database.
get-mailbox –datatbase Test –resultsize unlimited | new-moverequest –targetdatabase OtherDatabse
8. Remove the mailbox database from the target machine.
remove-mailboxdatabase –identity Test
9. Create a mailbox database with same name.
new-mailboxdatabase –name Test
10. Restore the same session again to the original location.
11. The database successfully mounts.