YouTube Videos Stuttering & Lagging on Firefox Until Restart

Recently I ran into a weird issue taking YouTube video courses using Firefox. When I opened a YouTube video it would play perfectly, but then if I switched tabs and came back to the YouTube video, the audio would be fine but the video would be freezing and pausing every few moments. Restarting Firefox would fix the issue, but it was not an ideal situation.

How to Fix YouTube Freezing & Stuttering in Firefox

  1. In your browser, visit about:config
  2. Search for accessibility.force_disabled
  3. Change the value of accessibility.force_disabled from 0 to 1
  4. Restart Firefox.
  5. If that fails to work, try one of these other solutions.

After making these changes, YouTube videos proceeded to play back smoothly even if I opened 30 tabs and switched between them. Really, it was an odd issue to just pop up, considering I’ve been using Firefox as my main web browser for almost 20 years and I’ve never seen this particular issue before.

How did I figure out the solution? Well, after some searching, I found some 5 and 7 year old threads discussing pretty much the exact same issue. That is crazy, because I am running Firefox 78 ESR but this issue was present for some as far back as Firefox 29 and maybe even further back. There was a bunch of tips that I tried that didn’t work, but buried among the advice was the solution.

Other Solutions to YouTube Slow Downs & Stuttering in Firefox

If what worked for me didn’t fix things for you, then you may want to try one of these solutions instead:

  • Goto Firefox > Help > Troubleshooting Information > and select Restart with Add-ons Disabled. This will restart Firefox with all your addons disabled. If Firefox and YouTube work normally, then you know one of your addons is causing the issue. To figure out which one is the culprit, activate one plugin and deactivate all others and then test YouTube until the problem reoccurs.
  • Goto Firefox > Help > Troubleshooting Information > and select Refresh Firefox (warning, you will lose all your settings and other personalizations but will also have a fresh and stock version of Firefox.)
  • If you have an older or slower CPU then Google’s use of the VP9 encoder for YouTube videos might be the problem. You can fix this by using this Firefox addon which forces YouTube to serve you H.264/mp4 videos instead.
  • Goto Firefox > Preferences > General > Performance > and uncheck “Use hardware acceleration when available.” Now restart Firefox and see if the YouTube playback issue still persists.

I’m confident that one of these solutions will work for you, but please leave me a comment down below if none of these answers worked for you. I’m happy to help out. Anyway, that about concludes this quick troubleshooting guide. It was a weird enough issue that required some digging and testing so I figured I’d write this article to try and amplify the solution that worked for me. Thanks for reading and happy learning!

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