Hi, the tabs are above the address bar by default, so I'm guessing you were using an add-on which is no longer working properly. The default appearance is; [[Use tabs to organize lots of websites in a single window]]. So disable all add-ons/theme by testing in Firefox Safe Mode to see if the problems go away. [[Troubleshoot Firefox issues using Safe Mode|Firefox Safe Mode]] is a troubleshooting mode that temporarily turns off hardware acceleration, resets some settings, and disables add-ons (extensions and themes). '''If Firefox is open,''' you can restart in Firefox Safe Mode from the Help menu: * Click the menu button [[Image:New Fx Menu]], click Help [[Image:Help-29]] and select ''Restart with Add-ons Disabled''. '''If Firefox is not running,''' you can start Firefox in Safe Mode as follows: * On Windows: Hold the '''Shift''' key when you open the Firefox desktop or Start menu shortcut. * On Mac: Hold the '''option''' key while starting Firefox. * On Linux: Quit Firefox, go to your Terminal and run ''firefox -safe-mode'' <br>(you may need to specify the Firefox installation path e.g. /usr/lib/firefox) When the Firefox Safe Mode window appears, select "Start in Safe Mode". ;[[Image:SafeMode-Fx35]] '''''If the issue is not present in Firefox Safe Mode''''', your problem is probably caused by an extension, theme, or hardware acceleration. Please follow the steps in the [[Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems]] article to find the cause. ''To exit Firefox Safe Mode, just close Firefox and wait a few seconds before opening Firefox for normal use again.'' -------------- There are probably several add-ons which will allow tabs on bottom, of which this is one https://addons.mozilla.org/en-US/firefox/addon/squared-australis-tabs/ When you figure out what's causing your issues, please let us know. It might help others with the same problem. Thank you!