See https://github.com/rogerwang/node-webkit/issues/1197

This is a false positive. Please submit the file to Windows to report it as such:

https://www.microsoft.com/en-us/wdsi/filesubmission

There can be many reasons for this.

libva error: vaGetDriverNameByIndex() failed with unknown libva error, driver_name = (null)

If you get this error, enable the --disable-gpu flag:

Via package.json:

{
  "chromium-args": "--disable-gpu"
}

Via command line:

/path/to/nw . --disable-gpu

NW.js based apps are singletons. This means that successive launches will terminate immediately.

To kill the existing NW.js process:

1. ps aux to find the pid
2. kill XXXX where XXXX is the pid.

Refs: https://github.com/streamlink/streamlink-twitch-gui/issues/695#issuecomment-565476126