Can you provide a screenshot?

just to add, you can try to right click the space between url input box and search input box and choose customize there, then click reset.

I don't have a URL input box. That is the problem. Attached is a screenshot

try left click the icon in the square, or right click on icons in any of the circled area.

Get a blank customization screen when I right click on the reload, history, and bookmark icons and when I left click Firefox, there is an "enter address bar but I can't move it to the Add-on Bar because the Customize does not open.

on the blank customization screen, is there a button for "restore defaults"? it should be near the lower left corner.

Do you have an extension that moves the Tab bar to the down position?

Start Firefox in Safe Mode to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem.

• Switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance
• Do NOT click the Reset button on the Safe Mode start window

• https://support.mozilla.org/kb/Safe+Mode
• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

jackjack said

I lost my navigation bar and it is not on the View menu. Tried reinstalling Firefox but that did not work. Worse, after the reinstall, I cannot customize.

Just running it in Safe Mode fixed all the problems. I didn't do anything in Safe Mode but because the address bar showed in Safe Mode, I closed Firefox and then reloaded it and everything came up the way it was before I upgraded it.