Join the AMA (Ask Me Anything) with the Firefox leadership team to celebrate Firefox 20th anniversary and discuss Firefox’s future on Mozilla Connect. Mark your calendar on Thursday, November 14, 18:00 - 20:00 UTC!

This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

ابحث في الدعم

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

Most Youtube videos have an error

  • 3 ردود
  • 6 have this problem
  • 1 view
  • آخر ردّ كتبه Knaifhogg

more options

This started a few days ago, I have no idea how it started. Basically very many Youtube videos don't start in Firefox. They work fine in Chrome (although they don't seem to load instantly, takes a while to start). Here's a screenshot: http://i.imgur.com/z5XP0zU.png

What I've tried:

Reinstall Firefox Reinstall Flash Clear cache in both Firefox and Flash New profile in Firefox Change to HTML5 on Youtube (and turn off Flash in plug-ins)

The Youtube HTML5 page (https://www.youtube.com/html5) looks like this http://i.imgur.com/KlOSgOR.png. In Chrome it's all green.

Please help.

This started a few days ago, I have no idea how it started. Basically very many Youtube videos don't start in Firefox. They work fine in Chrome (although they don't seem to load instantly, takes a while to start). Here's a screenshot: http://i.imgur.com/z5XP0zU.png What I've tried: Reinstall Firefox Reinstall Flash Clear cache in both Firefox and Flash New profile in Firefox Change to HTML5 on Youtube (and turn off Flash in plug-ins) The Youtube HTML5 page (https://www.youtube.com/html5) looks like this http://i.imgur.com/KlOSgOR.png. In Chrome it's all green. Please help.

الحل المُختار

I seem to have solved the problem. I had to manually go remove all Java versions I had and install the newest one. I believe the auto-removal of older versions in the applet when you install didn't work, so I had many versions installed at the same time, and I guess Firefox didn't like that.

Basically all I had to do was go to Programs and Features, remove everything Java related and download it again.

Read this answer in context 👍 0

All Replies (3)

more options

To see "more green" you can enable Media Source Extensions support in Firefox by setting this pref to true on the about:config page.

  • media.mediasource.enabled = true

See:


Did you clear the YouTube cookies as well?

You may also have to clear the Flash local storage.

  • Windows Control Panel > Flash Player > Storage: Local Storage Settings
    • Remove a specific domain: Local Storage Settings by site
    • Remove all domains: Delete All and Delete Data

Flash Website Storage Settings panel:

Global Storage Settings Panel:

more options

If I set media.mediasource.enabled = true, Youtube stops working completely if I have enabled html5. There's a never-ending loading screen on the flash player. The other combinations of html5 on and off and this true or false appear to be the same (error).

Yes I have cleared both cookies and cache, browser and flash.

more options

الحل المُختار

I seem to have solved the problem. I had to manually go remove all Java versions I had and install the newest one. I believe the auto-removal of older versions in the applet when you install didn't work, so I had many versions installed at the same time, and I guess Firefox didn't like that.

Basically all I had to do was go to Programs and Features, remove everything Java related and download it again.