CVIRT.dll Is Missing From LabWindows™/CVI™ 2017

Updated Jan 9, 2019

Reported In


  • LabWindows/CVI 2017 Full
  • LabWindows/CVI

Operating System

  • Windows

Issue Details

I recently upgraded to LabWindows/CVI 2017. When I open one of my previous projects, I am getting a message that cvirt.dll is missing. 


From the LabWindows/CVI for Windows, Version 2017 Readme, you will see that the cvirt.dll was removed. The most common cause of the error is if you have a project that was built in an older version and recently upgraded to 2017. 

If you have an older version of LabWindows/CVI installed, this DLL will be at the file path C:\Windows\SysWOW64. If you don't have an older version of LabWindows/CVI installed, please contact National Instruments support and reference this article.

To find where your program is using the cvirt.dll and update it to the cvirte.dll, you can use the program Dependencies to locate where it's being called. 


Additional Information

Once you have a copy of the cvirt.dll please copy the DLL into the following folders:
  1. C:\Windows\System32
  2. C:\Windows\SysWOW64
This will allow LabWindows/CVI to locate the dll. Nothing needs to be changed at the registry-level for this to take effect.

If you are developing a DLL or updating an old one, use the newer cvirte.dll instead of cvirt to avoid errors like this moving forward.