Install latest version -> Video DownloadHelper 4.9.8 * https://addons.mozilla.org/en-US/firefox/addon/video-downloadhelper Also, -> [[Add-ons are disabled after updating Firefox#w_check-for-new-versions-of-your-add-ons|Check for new versions of All your Add-ons]] Check and tell if its working. --------------------------------------------------------------------------------------------- -> Update All your Firefox Plugins -> [https://www.mozilla.org/en-US/plugincheck/] * '''When Downloading Plugins Update setup files, Remove Checkmark from Downloading other Optional Softwares with your Plugins (e.g. Toolbars, McAfee, Google Chrome, etc.)'''

Or you could try MP4 downloader: https://addons.mozilla.org/en-US/firefox/addon/mp4-downloader/?src=ss