At least one connector on the highlighted element is currently assigned to the [Element Name]. In general items shouldn't be assigned to the Default Systems, but should be assigned as equipments or elements of a non-default system. Click the More Info button below for additional information on System Creation. 
   Namespace:   Autodesk.Revit.DB  
  Assembly:   RevitAPI  (in RevitAPI.dll) Version: 2015.0.0.0 (2015.0.0.0) 
Syntax
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