I have a single exchange 2007 SP1 server with all the updates running 4 databases in the first storage group and the public folder database in the 2nd storage group. I have the online maintance tasks running for the databases at different times of the day (all scheduled after midnight with different start intervals) and even when I schedule only 1 database to do it's task from midnight to 8am (others are not scheduled for that day), it fails to complete. My backups are done before midnight so I don't know what else is tripping it up. The few times it does complete, I can see from the logs that it takes approximate 3 -4 hours. Any suggestions on how to get this complete?

Do you get any specific event error message for the same?How did you confirmed that the online maintenance failed for the specific database?Follow the following KB for more information and closely review the application log for if there is any logical corruption on the database.Online Maintenance Database Scanning in Exchange 2007 SP1http://technet.microsoft.com/en-us/library/bb676537.aspx How to Configure Online Maintenance Database Scanning in Exchange 2007 SP1http://technet.microsoft.com/en-us/library/bb676454.aspxArun Kumar | MCSE - 2K3 + Messaging | ITIL-F V3