The Add Join tool matches and joins the records in the Join Table to the records in the input Layer Name based on a common field. When attempting to browse for a shapefile, feature class, or table as an input in the Layer Name parameter, the data does not appear in the browsed folder location. For example, when attempting to create an Add Join geoprocessing model using ModelBuilder and browsing for a shapefile as the Layer Name input, the shapefile does not appear.
In some instances, selecting a table as the Layer Name input results in a complete join, and no error or warning is returned, but none of the fields from the joined table are present when viewing the joined attribute table.
This is by design. The Add Join tool only accepts a feature layer, table view, or raster layer with a raster attribute table as an input to the Layer Name parameter and does not accept a shapefile, feature class, or table as the input. For more information on the Add Join tool and the supported data types for the Add Join tool input, refer to ArcGIS Desktop: Add Join.
Note: The created feature layer is temporarily stored in memory; it is not saved on disk and only remains available within the current session. The layer is deleted once the session is closed. The feature layer can be saved to disk as a layer file using the Save To Layer File tool or saved as a new feature class using the Copy Features tool.
Note: The created table view is temporarily stored in memory; it is not saved on disk and does not persist after the session ends unless the document is saved.