Perform the following steps:
- Open the Group Policy Management Console (gpmc.msc).
- In the left navigation pane, expand the Forest node.
- Expand the Domains node, and then navigate to the domain where you want to link the GPO.
- Expand the domain name.
- Navigate to the OU where you want to enforce the GPO link.
- Expand the OU.
- Right-click the GPO link you want to enforce and click Enforced in the menu to enable or disable it. A check mark indicates whether Enforced is enabled or not: