I'm using Firefox 26 in Windows 7 x64 SP1.Since yesterday I can't play Youtube HTML5 videos. I have the HTML5 player activated in http://www.youtube.com/html5 and when I try to play a compatible video, like this one: http://www.youtube.com/watch?v=BGBM5vWiBLo I get a big 'loading' animation and nothing happens.That same video is playing without a problem in Internet Explorer 11.
Thanks for your help.
Try Firefox Safe Mode to see if the problem goes away. Safe Mode is a troubleshooting mode, which disables most add-ons.
(If you're not using it, switch to the Default theme.)
Once you get the pop-up, just select "'Start in Safe Mode"
If the issue is not present in Firefox Safe Mode, your problem is probably caused by an extension, and you need to figure out which one. Please follow the Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems article for that.
To exit the Firefox Safe Mode, just close Firefox and wait a few seconds before opening Firefox for normal use again.
When you figure out what's causing your issues, please let us know. It might help other users who have the same problem.
Thanks for your answer. I tried Safe Mode and the issue still remains, only now the loading animation is smaller, yet nothing happens. I don't think this is an extension or plugin-related problem, since I don't have anything installed related to HTML5 or YouTube.
I had the same problem with Firefox and found out that the thing causing the problem was the Cooliris add-on. As soon as I deactivated it, videos started to play just fine at You Tube.
In safe mode, after quite a long time to load, the vid does start playing - but won't play continuously. Takes a long time to buffer a little bit, plays that bit, then another long time of the loading animation. Really sucks.
Check your "Plugins" http://www.mozilla.org/en-US/plugincheck/
Of course HTML5 bypasses/does not need plugins to work (Uses the container) . However could be causing problems trying to take precident over HTML5 (just a rectal extraction guess on that one) *grin* ________________________________________________
You can either disable the plugin or "Bypass Scanning" for the Plugins.
To Bypass Scanning for the plugins, see this Mozilla Help Article http://kb.mozillazine.org/Plugin_scanning
________________________________________________ You didn't mention the OS. Will assume Microsoft. (about:config)= Seach for: plugin.scan.plid.all (change to FALSE) this overrides even windows registry.
See rest of article for further tweaks (with individual renders __________________________________________________
To disable Plugins type about:addons
(opens the traditional addons screen).
Click PLugins. Disable what you wish.
Restart browser. This should work. Let us know.
If you prefer, (before changing anything)--you can do a "Plugin Diagnostic" instructions located here
Standard diagnostic - Firefox