Hello,

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.)

• On Windows you can open Firefox 4.0+ in Safe Mode by holding the Shift key when you open the Firefox desktop or Start menu shortcut.
• On Mac you can open Firefox 4.0+ in Safe Mode by holding the option key while starting Firefox.
• On Linux you can open Firefox 4.0+ in Safe Mode by quitting Firefox and then going to your Terminal and running: firefox -safe-mode (you may need to specify the Firefox installation path e.g. /usr/lib/firefox)
• Or open the Help menu and click on the Restart with Add-ons Disabled... menu item while Firefox is running.

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.

Thank you.

Clear the cache and cookies only from websites that cause problems.

"Clear the Cache":

• Firefox/Tools > Options > Advanced > Network > Cached Web Content: "Clear Now"

"Remove Cookies" from sites causing problems:

• Firefox/Tools > Options > Privacy > Cookies: "Show Cookies"

Hey Nellus91,

I've followed your instructions and i found out which extention was causing me the problem was adblock. Even though it didn't cause any problem previously it suddenly did. I had to change the setting on it to make the videos on youtube work again. But now i'm having to watch those bloody ads again. If there is any solution on making youtube work without the ads please do let me know.

I will also try the sugesstion by cor-el and see if that works too.

Try with NoScript or RequestPolicy

I had the same problem. I had to manually disable each plugin. Not just disable it in the options menu. Type "about:addons" in your address bar. it will give you the path to all add ons. go to each path and rename the file it gives you with a "X" in front of it. When all is said and done just install Adobe Flash Player with the link youtube gives you. Or use this link. http://get.adobe.com/flashplayer/. let it install and you problem should be fixed. make sure you dont have any other media player plugins enabled. Good Luck!!!