Sometimes, Firefox themes can be very bad visuals and make the user interface hard to use.

Here are the steps to turn off, disable and uninstall a Firefox theme:

1. At the top of the Firefox windowOn the menu bar, click on the Tools menu and select Add-ons. The Add-ons window will appear.
2. In the Add-ons window, select the Extensions panel or Themes panel.
3. Select the add-on you wish to uninstall.
4. Click the Uninstall button. When prompted, click Uninstall to confirm.
5. If prompted, click Restart Firefox to finish uninstalling the add-on.