Activation and Deactivation buttons display on the Domain Watch > Probe Deployment tab, but only if the Directory Services Feature Set is installed.
Activation - Enables incremental discovery and synchronization of domain controller data. Activating a probe on a domain computer deactivates any other probe on that same domain, without loss of data.
Note: Activation is not required to run full sync on the Domain Watch > Schedule and Status tab.
Deactivation - Disables incremental synchronization updates from the domain. If reactivation occurs later, a "changes gap" may exist in the data collected by the probe, requiring the scheduling of a full synchronization to correct.