Exchange 2003 - How can I confirm mailbox store database mainteanance started and completed succesfully

You should be looking at your application event log to see event IDs 703, 704 and 1221 to learn more about the process status. Please refer http://technet.microsoft.com/en-us/library/bb691410.aspxfor more information.MMilind Naphade | MCTS:M | http://www.msexchangegeek.com

I only see Event 1221 None of the 700's. If I understand correctly I will enable MSExchangeIS Diagnostic Logging (if I understand correctly) to minimum to see if the 700 errors start appearing. By chance do you know why VSS process such as backups, snaps appear that can cause conflicts with this process

VSS, snapshots or online backup will only interfere when the backup time and the online maitenance time confilcts. You can configure your online defragmentation schedule accordingly. Yes, you are correct you will have to increase the logging at least to minimun but you will also have to make sure that the online defragmentation is configured correctly on the servers.MMilind Naphade | MCTS:M | http://www.msexchangegeek.com