In our tests, the process is terminated, even though the Terminate call returns an error. You can configure the step to continue building on failure.
https://kinook.com/VisBuildPro/Manual/stepfailure.htm
Alternatively, use a Run Program step with a command of
taskkill /im firefox.exe /f
https://kinook.com/VisBuildPro/Manua...gramaction.htm
https://docs.microsoft.com/en-us/win...mands/taskkill