Exchange Server Database Unmountable After Applying SP3 or Later

Service Pack 3 (SP3) and later for Exchange Server include several security and performance enhancing improvements that provide the user more customized experience. You are recommended to always perform a complete database backup before installing the update on your Exchange Server computer. This is because installing the update and upgrading Exchange Server might render the database unmountable. In such cases, you require to use your current database backup to restore it or perform effective Exchange Recovery using third-party tools. To exemplify, consider that you use Exchange Server 2000 SP2 and attempt to upgrade it to Exchange Server 2003.

When you try to mount the database, you might come across the below entry in application log of Event Viewer: Event Type: Error Event Source: ESE Event Category: General Event ID: 505 Description: Information Store (2028) An attempt to open the compressed file "drive:\Exchsrvr\MDBDATA\priv1.edb" for read / write access failed because it could not be converted to a normal file. The open file operation will fail with error -4005 (0xfffff05b). To prevent this error in the future you can manually decompress the file and change the compression state of the containing folder to uncompressed. Writing to this file when it is compressed is not supported. You might also receive an event with 9519 ID that suggests it failed to attach Jet DB.

Cause:

Exchange Server SP3 and later cannot mount compressed information store databases. This is because compressing database files invalidates sector independence, which is required by ESE to perform log-based recovery. So, if pre-SP3 Exchange Server contains NTFS compressed database, it will not mount. Also, such compressed databases can get corrupted 

Solution 

To isolate the given issue, use the following sequence of steps: 

• Dismount all the databases. 
• You can then decompress the folder of logs and databases
• Use eseutil /d to perform offline defragmentation of databases 

However, if you find your database corrupt due to NTFS compression, you should restore from the available backup. If this doesn't give the desired outturn, you need to use an Exchange Server Software to repair and restore the database.

Exchange Server Recovery tools employ high-end database repair algorithms that too reliably and safely. Stellar Phoenix Mailbox Exchange Recovery is a high-end Exchange Recovery Tool to safely extract all the mailboxes from damaged databases created with Exchange Server 5.5, 2000 and 2003. It is a non-destructive Exchange Server Software that can restore all objects including emails, email properties, tasks, drafts and more.

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