When a plugin fails, is outdated, or is simply missing, it will generally display an alert that will link to a site from which you will be able to download what you need. For this article, we'll find and install a missing Adobe Flash Player extension.;
, Most alerts will direct you to the download page.



In this example we will save the Disk Image to the desktop, then double click to open it.
 This will allow the installer to work. Should you omit this step, Firefox will prompt you to close the application before continuing.
 You will likely need to agree to all terms and conditions before downloading the software. Read the licences, and if agreeable, click "Continue," or "Install," or whatever word the software uses to move you to the next step: installing the software.
 Launch Firefox, and from the Tools menu, select Add-ons.


In the Add-ons Manager window, verify that your add-on or plugin in the list and enabled. (There will be a button that says "Disable" if the add-on is enabled.)
Check the functionality. Return to the page that required the plug-in and verify that it is now working.
Click on the link.
Download the plugin.
Follow the procedures to download the software.
Close and quit Firefox.
Run the installer application or installer wizard.
Verify installation.
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