Proof of the issue would help your case. I'm also having issues with YT, but I see comments. see screenshots https://www.youtube.com/watch?v=FsvjFKGsDg4 What security software besides MS Defender are you running? Windows home or pro? If you're running Windows Pro version, I would test in the Sandbox to confirm. https://www.howtogeek.com/399290/how-to-use-windows-10s-new-sandbox-to-safely-test-apps/ Did you try with Firefox in Troubleshoot Mode? https://support.mozilla.org/en-US/kb/diagnose-firefox-issues-using-troubleshoot-mode#search