Disable installing of add-ons in Firefox

Mozilla Firefox is very popular not only because it is very secure but also because it is highly customizable. You can install tons of add-ons and increase Firefox functionality. But the add-ons should only be installed from a trusted source. If you share the computer with family and do not want kids to install just any add-on found on the internet, then you can disable installing of add-ons in the Firefox. Here is how :

  1. Start Mozilla Firefox.
  2. Type about:config in the location bar and press Enter.
  3. Firefox will show a warning. Click on the button labeled I’ll be careful I promise! to proceed.

  4. In the Filter field type xpinstall. You would see a preference named xpinstall.enabled as shown.

  5. It has a default value of true. Double click on xpinstall.enabled to change its value to false to disable the installation of any add-ons. Now if you click on any add-ons link or open any add-on stored on your hard disk, Firefox will just ignore it.
  6. After changing the value, you do not have to restart the browser for the changes to take effect.