Instead of manually selecting one or more SharePoint sites for near real-time DLP event monitoring in SharePoint, when an Office 365 admin installs and opens the Secure Content Integrator app, an option to automatically monitor all SharePoint Sites in that Office 365 tenant is shown. If you select that option, it triggers a background job that registers all SharePoint Sites for event monitoring (including any new SharePoint Sites created in the future).
If you choose this option, you are still redirected to the page which tries to load all SharePoint sites for selection, but you don't need to wait for the page to be loaded, and you don't need to manually choose any SharePoint sites for event monitoring. At this point, you can choose to close the browser window and the event listener registration continues to happen in the background.
A background job is triggered as soon you click Submit and all SharePoint sites are registered for event monitoring in the background (including any new SharePoint sites that are created from that point onwards).
What happens if I select the Automatic monitoring option and deselect this option later?
All sites that were registered as part of the background job are still monitored. Navigate to the site configuration page and select the Stop Monitoring option for those sites.
Any new sites that are created after you deselect this option are not monitored automatically.