Sometimes, the video or audio content in a web page cannot be properly downloaded and displayed in Firefox. A required plugin may be missing, outdated, blocked, in conflict with another plugin or extension, or the content may be blocked for some reason. This article will help you solve these problems.

Plugins

Install missing plugins

Although Firefox can display some media on web pages such as images and open media like Ogg and WebM videos, it may need the help of media players and browser plugins for video, audio, and other content. Although you may have the correct media players installed to play video and audio files, you may be missing the necessary plugins when the media is embedded within the web page itself.

When a plugin is missing, do the following:

1. Click on the download link.
   
2. Then follow the instructions.

In case the installation fails, install it manually.

• Flash plugin: See How do I install the Flash plugin? and Managing the Flash plugin
  • The Flash plugin is used for many types of embedded audio and video, including YouTube.com videos.
• Java plugin: Using the Java plugin with Firefox
• Silverlight plugin: See Using the Silverlight plugin with Firefox
• Windows Media Player plugin: See Using the Windows Media Player plugin with Firefox
  • The Windows Media Player plugin will only play a specific few Windows media formats (.asf, .asx, .wm, .wma, .wax, .wmp, .wmv, and .wvx) unless the web page is specifically designed for Firefox and other Mozilla browsers. Internet Explorer will use Windows Media Player for many other formats like mp3 and midi, but Firefox will require another plugin, such as QuickTime.
• QuickTime plugin: See Using the QuickTime plugin with Firefox
  • The QuickTime plugin can handle many different types of embedded media. On older operating systems, the QuickTime plugin may not be configured to handle some common file formats found online, such as embedded .mp3 audio on Windows XP or Mac OS X 10.5 and below. In such cases, you need to select the media formats you want QuickTime to play in Firefox in your QuickTime Preferences.

For other uncommon embedded media, see Using the Shockwave plugin with Firefox, Using the RealPlayer plugin with Firefox, and the VLC download page at videolan.org

Update your plugins

Check that you have the latest versions of all your plugins.

• Go to our Plugin Check page and follow the links to update any plugins that are out of date.

Allow Plugin Container in your Internet security program

Allow your Internet security software (including firewalls, antivirus programs, anti-spyware programs, and more) to trust plugin-container.exe also known as Plugin Container for Firefox. For detailed instructions, see Firewalls where in this case Firefox means Plugin Container for Firefox.

Disable a conflicting plugin

If you have more than one plugin installed that can handle the same media type, this can cause a conflict that prevents some embedded media from playing. You may be able to fix the issue by disabling one of the plugins.

1. At the top of the Firefox window, click on the Firefox button (Tools menu in Windows XP), and then click Add-onsOn the menu bar, click on the Tools menu, and then click Add-onsAt the top of the Firefox window, click on the Tools menu, and then click Add-ons. The Add-ons Manager tab will openAt the top of the Firefox window, click on the Tools menu, and select Add-onsOn the menu bar, click on the Tools menu, and select Add-onsAt the top of the Firefox window, click on the Tools menu, and select Add-ons. The Add-ons window will open.

2. In the Add-ons Manager tabwindow, select the Plugins panel.
3. In the list of plugins, select the plugin you wish to troubleshoot.
   • If you want to disable the plugin, click the Disable button.
   • If you want to re-enable the plugin, click the Enable button

For example, you may need to disable the VLC plugin to play embedded QuickTime or Windows Media content. For more information about troubleshooting problems caused by plugins, see the Troubleshooting plugins article.

Other solutions

Clear the cache

See How to clear the cache.

Disable interfering extensions or ad-blocking software

• Ad-blocking software or extensions such as Flashblock or Adblock Plus can prevent audio or video content from playing. If the site works with ad-blocking disabled, you may want to add the site to your whitelist in your adblocker filter.
• Any Firefox extension can also block plugins. If the video or audio plays when you disable all extensions, then one of your extensions was causing the problem. For more information, see Troubleshooting extensions and themes.

Check some Firefox settings

• Verify that cookies are enabled in the Privacy panel in the OptionsPreferences window. Verify that the site is not blocked in the Cookie Exceptions list.
• Allow the website as an exception in the Firefox pop-up blocker. The "Block pop-up windows" option is found in the Content panel of the OptionsPreferences window.
• Verify that JavaScript is enabled in the Content panel of the OptionsPreferences window.

Remove specific entries in the hosts file (advanced users)

If you use a hosts file, you can temporarily disable it by renaming it Xhosts. Or, you can edit the hosts file to remove specific entries such as ad.doubleclick.net that can cause videos on certain sites to fail (for more information, see this MozillaZine forum thread). To apply changes to your hosts file, you may need to flush the DNS cache by entering the command: ipconfig /flushdns in the Run dialog box on Windows.

Based on information from Video or audio does not play (mozillaZine KB)