SPServiceInstance.SystemService property

Gets a Boolean value that indicates whether the service is a system service.

Namespace:  Microsoft.SharePoint.Administration
Assembly:  Microsoft.SharePoint (in Microsoft.SharePoint.dll)

public virtual bool SystemService { get; }

Property value

Type: System.Boolean
true if the service is a system service; otherwise, false.

System services cannot be started or stopped through the user interface in SharePoint Central Administration.