TestStand Unable to Locate Python on Windows

Updated Jun 9, 2026

Reported In

Software

  • TestStand

Programming Language

  • Python

Issue Details

NI TestStand is unable to locate Python. This occurs even though python.exe is installed correctly and included in the system Environment PATH. When attempting to run Python steps or configure the Python adapter, TestStand reports that it cannot find or launch Python. For example below error:

 

Solution

TestStand does not rely solely on the system PATH to locate Python.
Instead, it uses:

  • The Python Adapter configuration inside TestStand
  • The Windows Registry (PEP 514–compliant Python registration)

If either of these is missing or incorrect, TestStand will fail to detect Python even though it is installed and usable from the command line. To solve this issue, you can refer to the steps below:

 

Option A: Configure Python Directly in TestStand (Recommended)

  1. Open TestStand
  2. Navigate to: Configure » Adapters… » Python » Configure
  3. Set the following:
    1. Version: 3.13 (or your installed Python version)
    2. Executable Path: C:\RobotFramework\python3\python.exe
  4. Click OK
  5. Close and restart TestStand


In most cases, TestStand should now locate and launch Python correctly.


 


 


Option B: Fix the Windows Registry (PEP 514 Compliant)


Note: This requires Administrator privileges. Modify the registry carefully.


If the issue persists after configuring the adapter manually, ensure that Python is registered correctly in the Windows Registry.




Steps:


  1. Press Windows + R
  2. Type regedit and press Enter
  3. Click Yes if User Account Control (UAC) appears
  4. Go to Python Registry Key and go to this path:

    • image.png
    

  5. Make sure you are exactly at InstallPath
  6. Set Value data to: C:\RobotFramework\python3\

    • image.png
    

  7. Lastly, close TestStand and reopen it. TestStand should now find and launch Python correctly.





                                    

                                    

                                       
                                            
Additional Information


  • Adding Python to the system PATH alone is not sufficient for TestStand.
  • NI TestStand follows PEP 514 to discover Python installations.
  • For portable or custom Python installations, manual adapter configuration is the most reliable approach.



                                    


                        

                    

                

 
                
                

                

                

                    

                        

                            
                            

                                

                                    

                                                

                                                    
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