Did you try running it "Private Mode window" as well?

Yup, same issue.

That would indicate your firefox install is corrupted and messed up. And might require a complete removal and all folder deleted. Have you tried to create a different profile and try to see what happens as well?

https://support.mozilla.org/en-US/kb/profile-manager-create-remove-switch-firefox-profiles

Try this before doing the removal and see if the MODs might see what they could say to do next.

I uninstalled and reinstalled Firefox plus deleted all related folders. Youtube videos started working again that day and all day yesterday. It was working most of today until just a few minutes ago when the problem started occurring again with the buffering and the video not loading.

Boot the computer in Windows Safe mode with network support to see if that has effect in case security software (Webroot) is causing problems.

• https://www.bleepingcomputer.com/tutorials/how-to-start-windows-in-safe-mode/
• https://www.digitalcitizen.life/4-ways-boot-safe-mode-windows-10/

Haven't had a chance to try safe mode yet, but I see after I received the most recent update 107.0 that youtube videos are working again. I'll give it a day or two just in case, and if everything holds up I'll close this thread as solved.

It's been about five days and no issues, so I think I'm good. Thank you for the assistance, everyone!

I have this problem too, but reinstalling FF did nothing!