When the App Control database is installed on SQL Express a few Shepherd Config parameters are set to control the growth of the database files. This is due to the size limitation imposed by Microsoft when SQL Server Express is used.
Resolution
Please do NOT change any other properties on the shepherd_config page as it will cause your installation to behave unexpectedly or break.
Log in to the Console and navigate to https://ServerAddress/shpeherd_config.php
Find the Property: MaxDatabaseSizeMB and change the Value to: 0
Find the Property: DisableTrackingCutoffDatabaseSizeMB and change the Value to: 0