This policy setting allows you to specify which add-ins are always enabled, always disabled (blocked), or configurable by ...

This policy setting allows you to specify which add-ins are always enabled, always disabled (blocked), or configurable by the user. To block add-ins that are not managed by this policy setting, you must also configure the "Block all unmanaged add-ins" policy setting.To enable this policy setting, provide the following information for each add-in:In "Value name," specify the programmatic identifier (ProgID) for COM add-ins.To obtain the ProgID for an add-in, use Registry Editor on the client computer where the add-in is installed to locate key names under HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office\MS Project\Addins or HKEY_CURRENT_USER\SOFTWARE\Microsoft\Office\MS Project\Addins.You can also obtain the ProgID of an add-in by using Office Telemetry Dashboard.In "Value," specify the value as follows:To specify that an add-in is always disabled (blocked), type 0.To specify that an add-in is always enabled, type 1.To specify that an add-in is configurable by the user and not blocked by the "Block all unmanaged add-ins" policy setting when enabled, type 2.If you disable or do not enable this policy setting, the list of managed add-ins is deleted. If the "Block all unmanaged add-ins" policy setting is enabled, then all add-ins are blocked.