Hi, We are using Python for .Net to create an API. C# Assembly is called by Python script to access API methods. import sys sys.path.append(r"C:\myfolderA\myfolderB") print sys.path import clr clr.FindAssembly(r"AA.BB.CC") clr.AddReference(r"AA.BB.CC") from AA.BB.CC.Api.DDInterface import DDClient On the above line I am getting following error Traceback (most recent call last): File "C:\myfolderA\myfolderB\testAPI.py", line 7, in <module> from AA.BB.CC.Api.DDInterface import DDClient ImportError: No module named AA.BB.CC.Api.DDInterface There is no other information available to exactly identify the issue. Dlls from same project built 15 days back works fine. This project may have gone through few changes in between. How to exactly identify this issue? Could this be a dependency issue? I tried code decompile to compare old dlls and new ones. Couldn't find anything unusual. I am using Python27 Your help is deeply appreciated. Thanks, Murali