Invalid layer path in Map.addLayer()

Error Message

When attempting to add a layer file to a map using the addLayer() method in ArcGIS Pro, an error similar to the following occurs: 

ValueError: C:\path\to\layer_file\.lyrx

Example Code Triggering the Error

aprx = arcpy.mp.ArcGISProject("CURRENT")
m = aprx.listMaps("Map")[0]
m.addLayer(r"C:\path\to\layer file\.lyrx")  #Fails with ValueError

Cause

The error occurs because the Map.addLayer() method strictly requires either:

• A Layer object, for example, from map.listLayers(), or
• A LayerFile object, for example, created via arcpy.mp.LayerFile()

Passing a raw file path, “C:\path\to\file.lyrx", for example, directly to addLayer is unsupported and raises a ValueError.

Solution or Workaround

Convert the layer file path to a LayerFile object before calling addLayer:

1. Create a LayerFile object:

lf = arcpy.mp.LayerFile(r"C:\path\to\file.lyrx ")

2. Add the output to the map:

aprx = arcpy.mp.ArcGISProject("CURRENT")
m = aprx.listMaps("Map")[0]
m.addLayer(lf) #Successfully adds the layer to the map.

Final Sample Code: Adding a Layer File to a Map

import arcpy
# Load the current project and reference the map
aprx = arcpy.mp.ArcGISProject("CURRENT")  # Use "CURRENT" for active project
map_obj = aprx.listMaps("Map")[0]  # Replace "Map" with your map name
# Convert layer file path to a LayerFile object
lyrx_path = r"C:\path\to\your\layerFile.lyrx"  # Update with your path
lyrx_file = arcpy.mp.LayerFile(lyrx_path)
# Add to map
map_obj.addLayer(lyrx_file)
print("Layer added successfully!")

For more information about working with layers and maps in ArcGIS Pro, refer to the documentation in the Related Information section.