Your System Details list shows: Shockwave Flash 15.0 r0 Try to delete the pluginreg.dat file in the Firefox Profile Folder and maybe addons.sqlite as well to reset the plugin registry databases. See Re-initializing the plugins database: *https://support.mozilla.org/kb/troubleshoot-issues-with-plugins-fix-problems You can use this button to go to the currently used Firefox profile folder: *Help > Troubleshooting Information > Profile Directory: Show Folder (Linux: Open Directory; Mac: Show in Finder) *http://kb.mozillazine.org/Profile_folder_-_Firefox ---- You can try to uninstall the current Flash player version and (re)install the latest Flash version. See this about uninstalling Flash players: *http://helpx.adobe.com/flash-player/kb/uninstall-flash-player-windows.html Note that this will remove all installed Flash players. You can find the latest Flash player versions for Firefox on this page: *http://www.adobe.com/special/products/flashplayer/fp_distribution3.html