• You have restarted the Enforce server or restarted the Detection Server Controller service (formerly Monitor Controller service) and see that the service stops again after about 30 seconds. 
• You may have recently changed some settings in the \Symantec\DataLossPrevention\EnforceServer\15.x\Protect\config\Manager.properties file
• Permissions to all the configuration files appear to be correct
• Investigation with Procmon however, shows that Windows is unable to access the Manager.properties file

In the MonitorContoller.log file, you see entries such as: 

Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.vontu.communication.services.file.receiver.FolderMonitoringAndCleanUpTasks]: Factory method 'getIncidentFolderTasks' threw exception; nested exception is com.vontu.util.config.ConfigurationException: Configuration parameter "max_incidents_in_folder" isn't set.

    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:185)

    at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:582)

    ... 69 more

14.x, 15.x, 15.8

The Manager.properties file has become corrupted

1. Run chkdsk /f on the Enforce server to repair the disk file system
2. Replace the Manager.properties file with a known good one from another server or copy its contents to a newly created Manager.properties file and copy it into the \Symantec\DataLossPrevention\EnforceServer\15.5\Protect\config\ folder
3. Restart the Detection Server Controller service