The Adobe Flash Player browser plugin lets you view video and animated content in Firefox. This article has information about testing, installing, updating, uninstalling and troubleshooting the Adobe Flash plugin.
Visit Adobe's test page to see if the Flash plugin is installed and working properly. If it tells you that Flash is not installed, see the article Install the Flash plugin to view videos, animations and games or see the next section on how to install the latest Flash plugin.
The Flash plugin automatically updates itself by default. If Mozilla's Plugin Check page or Adobe's test page says that Flash is outdated and you don't want to wait for the automatic update, you can update Flash manually by downloading and installing the latest version from Adobe.
To check if your installation of Flash is up to date, visit Mozilla's Plugin Check page. If it says that Flash is outdated, you can update Flash by downloading and installing the latest version from Adobe.
If Adobe's test page does not show that Flash is working even though you have installed the latest version, your Flash plugin may be disabled. To make sure that Flash is enabled,
Click the menu button and choose Add-ons. The Add-ons Manager tab will open.
If the Flash plugin is disabled, select Always Activate in its drop-down menu.
There are three different types of Flash Players: an ActiveX version for Internet Explorer, a Chrome version built-in the browser and a plugin version for Firefox and some other browsers. If you want Flash to work in Firefox you must install the plugin version, as explained above.
If you see an "Activate Adobe Flash" prompt instead of Flash content, either you have set the Flash plugin to "Ask to Activate" in the Add-ons manager or Firefox has prevented an unsafe Flash version from running automatically. Click on the "Activate Adobe Flash" message to allow the Flash content to load (if it doesn't, reload the page and try again). For more information, see the articles Set Adobe Flash to "click to play" on Firefox and Why do I have to click to activate plugins?.
If you see this message instead of Flash content, see Adobe Flash plugin has crashed - Prevent it from happening again and Adobe Flash protected mode in Firefox.
Firefox will show you a warning dialog if the Flash plugin is taking longer than expected:
See the article Warning Unresponsive plugin - What it means and how to fix it for solutions and workarounds.
If Firefox stops responding or if the Flash plugin hangs or stops working when playing Flash videos or games, try these solutions:
Based on information from Flash (mozillaZine KB)