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.)

• You can open Firefox 4.0+ in Safe Mode by holding the Shift key when you open the Firefox desktop or Start menu shortcut.
• 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.

This did not solve the problem. It looks like the video wants to load and then it comes up with the error.

Does reading and following the instructions here help?

• Flash 11.3 doesn't load video in Firefox which applies to 11.3 and up

I downloaded the real player and it did not solve the problem. I then uninstalled FireFox (dragged to trash and emptied) then reinstalled through Chrome and it still doesn't work. Both Safari and Chrome will play YouTube videos.

Can you reproduce in a new profile/does it happen in a new profile?

• Profile Manager - Create, remove or switch Firefox profiles

This can be caused by corrupted cookies or cookies that are blocked (check the permissions in Tools > Page Info > Permissions or on the about:permissions page).

Clear the cache and the cookies 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"