How can resolve the error code -38 “WaveShaper Not Found” when using the API interface?

The error code -38 “WaveShaper Not Found” occurs whenever the API is unable to establish communication with your WaveShaper.

First confirm that there isn’t a hardware fault. Ensure that the  WaveShaper is powered on and connected to the computer via USB.

A Windows message bubble may appear indicating that the driver is being installed:

This is followed by a message saying that the driver is ready to use.

Once Windows connects to the WaveShaper, start up the WaveManager program. Check that you can successfully apply a filter using WaveManager.

If the WaveShaper cannot connect to the WaveManager then it indicates a device communication issue such as a faulty USB cable or the USB drivers not installing correctly.

  • Plug and unplug the USB cable
  • Replace the USB cable
  • Reboot the computer
  • Reinstall the WaveManager program
  • Email us at if you cannot connect using WaveManager

If the WaveManager works then it is an issue with the API not being able to see the unit. The software is successfully interfacing with the API (wsapi.dll) but the drivers are not up to date or not copied to the local folder.

Ensure that the file paths used in your program connect to the location where the wsconfig file is located. If you’re not sure where this file is, you can easily navigate to it by loading WaveManager, selecting File -> Open WaveManager Data Folder, and double clicking on the wsconfig folder.  Copy the wsconfig file from there to your program location.

Do not run the WaveManager program and the API call at the same time. Make sure that you quite WaveManager before attempting to communicate with the WaveShaper through the API.

It’s highly recommended that wsapi.dll, ftd2xx.dll and ws_cheetah.dll be copied to the local folder where you have installed your software to communicate to the WaveShaper. Note that there are two different versions of .dll for 32 bit and 64 bit operating systems.

For the 32-bit operating system, these are the relevant DLLs:

  • C:\Program Files (x86)\Finisar\WaveManager\waveshaper\api\wsapi.dll
  • C:\Program Files (x86)\Finisar\WaveManager\waveshaper\api\ftd2xx.dll
  • C:\Program Files (x86)\Finisar\WaveManager\waveshaper\api\ws_cheetah.dll

For the 64-bit operating system, these are the relevant DLLs:

  • C:\Program Files (x86)\Finisar\WaveManager\waveshaper\api\lib\amd64\wsapi.dll
  • C:\Program Files (x86)\Finisar\WaveManager\waveshaper\api\lib\amd64\ftd2xx64.dll

In addition for 64-bit ftd2xx64.dll should be renamed to ftd2xx.dll after copying.

To download WaveManager with the latest drivers, please use this direct link:


Please rate this article