Do you mean you want to disable the "Smart HTTPS" add-on? You can view, disable, and often remove unwanted or unknown extensions on the Add-ons page. Either: * Ctrl+Shift+a (Mac: Command+Shift+a) * "3-bar" menu button (or Tools menu) > Add-ons In the left column, click Extensions. Then cast a critical eye over the list on the right side. All extensions are optional. If in doubt, disable. Often a link will appear above at least one disabled extension to restart Firefox. You can complete your work on the tab and click one of the links as the last step. ---- If you meant something else, could you describe the problem in more detail? Normally the website decides whether you are forced to use HTTPS, not Firefox.