Undefined Symbol "ASyncTimer" in LabWindows/CVI™

Updated Jun 3, 2021

Reported In


  • LabWindows/CVI

Issue Details

I have a LabWindows/CVI project that compiles correctly, but when I try to link the project to its dependencies, I get an error designating "ASyncTimer" and related functions as undefined symbols.


This error is due to the ASyncTimer not being correctly added in your LabWindows/CVI environment. You can correct this by following the below steps.
  1. On the LabWindows/CVI toolbar, go to Library >> Customize.
  2. In the dialog box that pops up, click Browse, and browse for the asynctimer.fp file - for most devices, this will be at the following location: C:\Program Files (x86)\National Instruments\<Your LabWindows/CVI Version>\toolslib\toolbox.
  3. Once asynctimer.fp is added, restart LabWindows/CVI. When you next attempt to compile/link the project, you should be able to do so successfully.

Additional Information

Similar issues with linking other libraries/functions can be solved the same way if they are not listed as a user library in the Library >> Customize dialog box.