Digilent MCCDAQ Universal Library for LabVIEW Cannot Load in TestStand

When I try to use my LabVIEW VIs that rely on the MCCDAQ Universal Library for LabVIEW (ULx) in a TestStand sequence configured to use the LabVIEW Run‑Time Engine as the adapter, I receive an error stating that TestStand is “Unable to load VI … with the LabVIEW Run‑Time Engine.” The detailed error message reports that ULx_LV.dll cannot be found, even though the DLL is present in the exact path shown in the error message.

The ULx VIs run correctly in the LabVIEW development environment and also run successfully in TestStand when the LabVIEW Development Environment (ADE) is selected as the adapter, so the VIs themselves are not broken. I verified that the DLL and its dependencies are present in the appropriate Windows system directories, but TestStand still reports that the DLL cannot be loaded when using the Run‑Time Engine.

I also noticed that earlier versions of TestStand and the LabVIEW Run-Time Engine are able to load the same VIs and DLL without any issues.

To work around this limitation, you can use one of the following approaches:

• Use the LabVIEW Development Environment as the adapter in TestStand.
  The LabVIEW ADE can still load .NET Framework assemblies, so ULx‑based VIs load correctly when this adapter mode is used.

• Call ULx_LV.dll directly using the TestStand .NET Adapter.
  TestStand may be able to load the .NET Framework DLL directly, even though the LabVIEW Run‑Time Engine cannot load it under a .NET Core host process.