Data Security starts scanning files and matching them against enabled 
user activity rules as soon as you save a new policy or modify an existing
            policy. The default action is to generate a log when a policy violation occurs but if
            you enabled email alerts for high-risk issues, you will also receive an automatic email
            notification. To view policy violations for user activities, select . If no known violations for user activity policies display, consider that
            activity monitoring for some cloud apps depends on 
user activity requirements.