Hi, Please check if this happens in [https://support.mozilla.com/en-US/kb/Safe%20Mode Safe Mode]. While in Safe mode you can also try to '''Disable''' all the '''Plugins''' except Flash in '''Tools''' ('''Alt''' + '''T''') > '''Add-ons'''. Safe mode disables the installed '''Extensions''', and themes ('''Appearance''') in '''Tools''' ('''Alt''' + '''T''') > '''Add-ons'''. Hardware acceleration is also temporarily disabled - the manual setting is '''Tools''' > '''Options''' > '''Advanced''' > '''General''' > [https://support.mozilla.org/en-US/kb/Options%20window%20-%20Advanced%20panel?as=u '''Use hardware acceleration when available''']. All these settings/options/add-ons can also be individually or collectively disabled/enabled/changed in Firefox normal mode to check if an extension, theme, option or hardware acceleration is causing issues. Disabling/enabling hardware acceleration, and some types of add-ons in normal mode may require a Firefox restart. [http://support.mozilla.com/en-US/kb/Uninstalling+add-ons Uninstalling Add-ons] [http://kb.mozillazine.org/Uninstalling_toolbars Uninstalling Toolbars] [https://support.mozilla.com/en-US/kb/Troubleshooting%20extensions%20and%20themes Troubleshooting Extensions and Themes] [http://kb.mozillazine.org/Problematic_extensions Problematic Extensions] [https://support.mozilla.org/en-US/kb/Options%20window Options] Please also note that the latest Flash player has a [http://helpx.adobe.com/flash-player/release-note/enduser-release-notes-11_3.html#main_Known_Issues known audio issue]. You can try to let the streaming finish and then start the playback.

You can check for problems caused by a recent Flash 11.3 update. *https://support.mozilla.org/kb/flash-113-doesnt-load-video-firefox