Pick a video downloader with a built-in player. Recommended options:
If you see this message frequently, even on trusted sites like YouTube or Vimeo, your computer may already be infected with a browser extension or program that injects fake video player prompts into web pages. Pick a video downloader with a built-in player
If you are on Windows and want a modern-looking player with many customization options, PotPlayer is an excellent alternative to VLC. Pick a video downloader with a built-in player