I Installed Python, but Teststand Doesn’t List the Python Version

Updated Sep 10, 2019

Reported In


  • TestStand

Issue Details

I installed TestStand and Python, but when I configure my Python Adapter, the dropdown down not list any Python Versions.

The Python Adapter shows a red exclamation point with the following error message: 

Unknown python version. TestStand supports 2.7+ and 3.6+. Specify the version with major and minor version number like ‘2.7’ or ‘3.6’. Make sure python is present in PATH environment variable. 

How can I fix this?


There are several important things to check when configuring Python to work with TestStand. 

  • Check to make sure that the PATH environment variable is properly configured. TestStand will search in the default directory for Python, but not all installations of Python are installed in this directory. You can follow the KnowledgeBase article on Editing the PATH Environment Variable for TestStand’s Python Adapter to add the path.
  • You will need to have the same bitness of TestStand and Python for the version to appear in the Python Adapter Configuration window. 32-bit TestStand will only work with 32-bit Python and 64-bit TestStand will only work with 64-bit Python. 
  • If you are using a virtual environment, you should check that the virtual environment is in the search directory and that the virtual environment exists. 
  • Restart TestStand if you have installed Python or edited the PATH environment variable since trying to find the Python version. A restart of TestStand and any TestStand tools is sometimes required to utilize a newly installed Python version or recently edited PATH variable.