Brick level mailbox backups contain corrupt items

We have a W2003SP2 R2 backup server running Backup Exec 11 Rev 7170 with SP3.

 

Dut to lack of disk space we are running brick level backups of Exchange 2003 mailboxes.

The mailboxes are backed up differentuially Monday-Thursday and then fully at the weekend.

 

In the full backup the first 100 mailboxes are backed up successfully but the remainder ( approx 160) are all showing as corrupt or containing corrupt items. Therefore it is not possible to restore maildata from them without receiving the error " message was corrupt before being backed up". The full backup logs are showing as "access denied" to all these messages but the logs do not display correctly and are in the region of 1Gb because of this.

 

Checking the mailboxes from Outlook all these messages are okay and available. They can be backed up and restored from when running tests throughout the day. It is also possible to restore the maildata by restoring the mailstore into a recovery storage group and then using the exmerge tool to export to pst (slightly long winded but works to my relief..!)

 

Given that the corruption starts onthe same mailbox each full backup I was thinking that there maybe another process running on either the backup or exchage server that is causing this. Indeed the exchange online defrag and Backup Exec db maintenance were running but have now been disabled.

 

Problem still remains though.

 

Anyone experienced any similar problems or have any suggestions?

 

Cheers.