.NET exception in Labview: System.ArgumentNullException  RRS feed

  • Question

  • Hi team,

    I keep getting the error:

    Error 1172 occurred at Property Node (Arg :1) Error accessing property Thorlabs.MotionControl.Benchtop.StepperMotorCLI.StepperMotorChannel.IsEnabled, (System.ArgumentNullException: Key cannot be null.
    Parameter name: key)

    Possible reason(s):

    LabVIEW:  A .NET exception occurred in an external assembly. For information about correcting this error, copy the following exception (in bold), and search the Microsoft Developer Network (MSDN) Web site or the Web for a possible explanation.
    System.ArgumentNullException in>>

    What am I missing?


    • Edited by imcompatible Thursday, December 27, 2018 6:53 PM
    Thursday, December 27, 2018 6:52 PM

All replies

  • Also the same thing but with this exception: 


    Thursday, December 27, 2018 7:06 PM
  • Hi friend,

    Welcome to the MSDN forum.


    Have you connected any third party device or virtual app in Labview? I find some members posted a valid solution that powered the device was not initialized because the power strip failed. Once I powered the device, it was able to initialize and the error was resolved.

     Did you add any specific assembly in there? Based on your error message. If possible, you can check if following thread is helpful: and

    Since our forum mainly focus on .NET Framework Setup and Servicing issue. Your issue is related to Labview. I recommend you redirect to Labview support forum and start a new thread for a more professional supporting.

    Thank you for your understanding.



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    Friday, December 28, 2018 5:57 AM