When you upgrade Microsoft Exchange Server to a later version, the upgrade process first upgrades the database before copying any code of the later version to Exchange Server computer. Then it makes corresponding changes in registry, services, and system. The reason is that in case the database upgrade fails, one is allowed to perform a complete rollback by doing operations like moving the mailboxes. But the situations become critical when the database is left in partially upgraded state and with no suitable recovery option other than backup. Another alternative to deal with such Exchange database corruption issues is to use a read-only exchange recovery utility.
Consider, you use Exchange Server 5.5 and attempt to upgrade it to Exchange Server 2003. Next, you notice that the upgrade operation cannot proceed successfully and an error message pops up that reads as below:
This error is associated with decimal value of -563 and hexadecimal value of 0xFFFFFDCD.
The above error is encountered when you attempt to upgrade the Exchange database, but it is only partially converted to the required database format. As a result, user cannot mount or use this database further.
The upgrade usually fails because the current system doesn't conform to the system requirements asked by the later version or the database is extremely fragmented (however, there can be other reasons as well). To prevent such post upgrade consequences, it is recommended to backup the database prior to upgrading. You can follow the below measures to extract data in such situations:
Try to move the mailboxes to another Exchange computer
Restore the database from the last available backup
Use a read-only exchange server recovery utility to repair and restore the database
Exchange Recovery software have great competence in fixing any sort of Exchange database corruption and in extracting the data. These utilities do not modify the integrity of original database and thus are safe to use.
Stellar Phoenix Mailbox Exchange Recovery is an advanced utility that repairs corrupted Exchange database and restores users' mailboxes in individual *.pst files. The software performs exchange recovery using powerful, yet safe, algorithms. With deleted mailbox recovery feature, the tool is compatible with Exchange Server 2007, 2003, 2000, and 5.5.