I recently had an issue where a client's Microsoft Exchange 2010 server failed the best practices analyzer due to an "Database backup critical" error. I was confused at first since I had a fully functional wbadmin scripted backup that I could see backed up Exchange. Only after fiddling for a while did I discover the missing parameter I had to provide before exchange indicated a successful database backup and subsequently cleared out all the thousands of database log files it kept:

wbadmin start backup -backupTarget:\\1.2.3.4\backups -include:c: ^
   -user:msbackup -password:"password" -quiet -allCritical -vssFull -systemState

Without -systemState this never worked.