LabVIEW Load Error Code 21: External Subroutine Required (App Note) | LabJack
 
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LabVIEW Load Error Code 21: External Subroutine Required (App Note)

We've had some reports of LabVIEW load error code 21: An external subroutine required for execution could not be found. This can include other error text, such as An error occurred loading VI 'Cosine Integral.vi' or a message saying lvanlys.dll is missing.

This error has happened in relation to loading LabVIEW-based applications like LJLogM or LJLogUD.

Troubleshooting

Generally, running the LabVIEW Runtime Engine installer fixes the issue.

If that doesn't fix the issue, check that you have LabVIEW 7.1 installed. See: Which Versions of LabVIEW Run-Time Engine Do I Have Installed?

If you're running a networked computer:

  • Please make sure lvrt.dll and lvanlys.dll are installed locally to the same drive as the LabVIEW application you're trying to run. See: Which Versions of LabVIEW Run-Time Engine Do I Have Installed?
  • Please make sure the National Instruments Math Kernel Library is installed locally to the same drive. It should be installed to National Instruments\Shared\MKL.