You need to uninstall Data Loss Prevention (DLP) Enforce, Detection Server, or Agent (Mac or Windows)
Please see the Installation Guide for DLP. Choose the correct version of DLP Installation Guide for which version you are using.
Specifically use the "Uninstalling Symantec Data Loss Prevention" chapter for Enforce. This section includes how to uninstall Enforce, Detection servers, Windows Endpoint Agent, and the Mac Endpoint Agent.
Should the Windows or Mac Endpoint Agent not be a completely clean uninstall, please open a support ticket.