TestStand Error -17801: Unknown Interface ID

Updated Jul 17, 2019

Reported In


  • TestStand
  • LabVIEW

Issue Details

I am using TestStand to call a LabVIEW VI that has a Waveform Parameter. When I try to call the VI, I get Error Code: -17801; Unknown Interface ID. How do I fix this error?


This error usually occurs if you uninstall LabVIEW but leave a different version installed.

To fix the problem, you will need to repair your LabVIEW installation.
  • Windows Control Panel
    1. Go to Settings » Control Panel » Add or Remove Programs.
    2. Choose National Instruments Software and click Change/Remove.
    3. Choose the version of LabVIEW that is still installed, and click Repair.
  • NI Package Manager does not currently have an option to repair an installation. Due to the lack of this feature, repairing an installation requires two steps:
    1. Uninstall the software in question
    2. Download and re-install the software in question