This may be caused by a recent Flash 11.3 update.

See:

• https://support.mozilla.org/kb/keep-flash-up-to-date-and-troubleshoot-problems
• https://support.mozilla.org/kb/flash-crashes-or-does-not-load-firefox-13

• http://forums.adobe.com/thread/1018071?tstart=0
• http://blogs.adobe.com/asset/2012/06/inside-flash-player-protected-mode-for-firefox.html

thats actually not the problem the videos play perfectly never crash. its after i pause them then press play again. after that i can't scroll down the web page no matter what.

Start Firefox in Diagnose Firefox issues using Troubleshoot Mode to check if one of the extensions or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance/Themes).

• Don't make any changes on the Safe mode start window.
• https://support.mozilla.org/kb/Safe+Mode

Try to disable hardware acceleration.

• Tools > Options > Advanced > General > Browsing: "Use hardware acceleration when available"

• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

just did the hardware acceleration thing and that didn't help. i think its just this version of firefox thats the problem. it only started since the last firefox update. i'll just use internet explorer for watching videos.

did anyone find a way to fix this?

Try to "disable the hardware acceleration" in the Flash Player.

• http://helpx.adobe.com/flash-player/kb/video-playback-issues.html

See also:

• https://support.mozilla.org/en-US/kb/keep-flash-up-to-date-and-troubleshoot-problems

Flash "Display settings" window:

• http://www.macromedia.com/support/documentation/en/flashplayer/help/help01.html

cool update! update stuff we really don't care about and F up the stuff we actually use. THX!

its still broken even after the latest update today wtf is wrong with firefox? make a update that will fix this

This is indeed a new problem. Happens on all pages with embedded youtube videos and really hurts the user experience. Please fix this as soon as possible.

I'm experiencing this same issue as well and the way to work around this bug is clicking once on the URL bar and it allows you to scroll again. It's not the best solution but it works for me. Hope there is an update soon to solve this problem.

I solved this problem by rolling back to Flash Version 11.2.202.235

hmm does that change anything like for any games or videos does it make anything get slower?

The older version of flash does not slow anything down or cause any problems with flash video or games for me

I fix it too!! Installing that flash version.

For x64 version: http://www.oldapps.com/flash_player.php?old_flash_player=7629

edgartaor the adobe flash player installer that installs the old one says the installation encountered errors the version of adobe flash player that you are trying to install is not the most current version. please visit the player download center to obtain the latest most secure version

You have to unnistall the Flash before install an older version. The current version have this issue.