Hi, You can try to '''Clear Now''' the '''Cache''', '''Cookies''', and '''Site Preferences''' in '''Tools''' ('''Alt''' + '''T''') > [https://support.mozilla.org/en-US/kb/Clear%20Recent%20History Clear Recent History] as well as '''Delete all''' in the Windows '''Control Panel''' > '''Flash Player''' > '''Storage''' tab. If you have security software (antivirus, firewall etc.) installed, you can try deleting all existing instances of Firefox and its related files in all the different configuration areas/modules of the security software. Instead create new allow/trusted rules for Firefox + its related processes. Even otherwise the security software may also ask again when Firefox is started and you can try to allow/trust at that time. Please see [https://support.mozilla.org/en-US/kb/Firewalls this]. [http://kb.mozillazine.org/Firewalls AV/Firewalls Configuration]

You can check for problems caused by a recent Flash 11.3 update and possibly downgrade to Flash 11.2 or 10.3. *https://support.mozilla.org/kb/flash-113-doesnt-load-video-firefox *https://support.mozilla.org/kb/flash-113-crashes