This issue occurs during nightly maintenance if the client site is licensed for Multimedia (MCC) and the backup of the client history fails.
Error
Maintenance finishes, but with errors. Backup files are only required to maintain client history linking.
When this issue occurs it is typically due to size limitations of the file format of the backup and the size of data in the database. Because of size limitations of our backup format and the large amount of data in being captured by exchange, you should move to a Microsoft SQL server backup model to retain this information. Then remove the MCC Backup from the maintenance tasks.
CCM 6.0