We have been using Backup Exec 10d for about 1.5 years with no trouble. In the last few weeks every morning Exchange becomes unresponsive, we can't send or recieve emails but the server is up. After a reboot Exchange is fine and the only error we get from Backup Exec is that the backup for the Exchange server failed at the time of the reboot but all other backups complete successfully. There are many errors in the system log of the Exchange server that would seem to indicate a communication problem. Error id 2103, 2104, 8025 and many others but also some error codes that indicate some sort of database conflict like error 7200 with cause 0x80004005 which I believe means there is a lock on part of the database.
After a two weeks of troubleshooting communication and database errors (running ISINTEG and making sure all the servers were up during the backup) we stopped the backups and the problem went away. The server runs fine and there are no errors in the system or application log. If we turn the backups back on we have the same problem. I can run a NTBackup on the exchange store during the same time that we would run the Backup Exec backup and the NTBackup works fine. There is no overlap in the exchange maintenance schedule and the backup scheduld.
We have made no changes to the backups in the last 1.5 years. I have rolled back all updates to before this problem began. I can't figure out what has changed that would cause this to happen. I have a ticket open with Microsoft and they can't find any problem with our Exchange server or our network.