Solutions

• Add or select a coordinate system for the reference feature class that is used for building the locator. Then create a new locator after a spatial reference is added to the reference feature class.
• If you are not able to add a spatial reference to the reference feature class, specify a new coordinate system in the Output Coordinates section on the Environment Settings window of the Create Address Locator dialog box when you create the address locator.

More information

By default, a locator stores the spatial reference of the reference feature class when the locator is built. It is important for a locator to have a spatial reference since it determines where the matched features should be placed on the map and the spatial reference to be used for the output feature classes generated by matching a table of addresses or reverse geocoding point locations. When creating a composite locator, the composite locator also requires a spatial reference that can be the same as the participating locators.