That's the funny (not so funny) thing about updates. Surprise. Ok I can suggest this then : Please uninstall Firefox. Then Delete the Mozilla Firefox Folders in C:\Program Files and C:\Program Files(x86) Then restart system. Then run Windows Disk Cleanup. Then run it again and click the button that says Cleanup System Files. Note: your Firefox Profile is saved.

Reinstall with Current Release Firefox 57.0 with a Full Version Installer https://www.mozilla.org/firefox/all/

Doing it this way gets rid of all previous left overs of updates and files.

Please let us know if this solved your issue or if need further assistance.

Will me bookmarks be saved? I think they will; I accessed them once before recently when something untoward happened. I recently rebuilt ALL my bookmarks and do not want to lose them. Please tell me how to back them up if I need to do this.

MaureenJordan said

Will me bookmarks be saved? I think they will; I accessed them once before recently when something untoward happened. I recently rebuilt ALL my bookmarks and do not want to lose them. Please tell me how to back them up if I need to do this.

Hi MaureenJordan,

If you have not set up up Sync on your computer (a free service from Mozilla to backup your Firefox data), take a look here: https://support.mozilla.org/en-US/kb/how-do-i-set-sync-my-computer

Thank you for using Firefox!

OK. I have saved your responses and will delve into this hopefully later today. Sigh. I will let you know if I get into trouble. I appreciate your quick responses.

firefox 57 also comes has a light theme that you can switch to when go to the firefox menu ≡ > addons > themes panel.

Hi MaureenJordan, if the above replies did not enable you to resolve the problem, or to help us confirm our comments, could you reattach the screenshot? You can use the Browse button below a reply textbox to upload it.

philipp said

firefox 57 also comes has a light theme that you can switch to when go to the firefox menu ≡ > addons > themes panel.

That worked! I changed it from Default to Light and the black background on toolbars and dropdown menus was replaced by white. Thank you.

Well mine turned to light gray color, an improvement but I wanted white. What is concerning is that the "default" is black. So perhaps uninstalling and re-installing may not work. I have not had time to do that yet.

the firefox default theme will also adhere to what you've set in your win10 system settings under personalisation > colours if you toggle the switch to apply this for titlebars.

Appreciate. White is not an option; my very light turquoise are my accent colors but not for tabs. Thanks again for suggestion. I wonder if anyone has white tabs anymore. I will sync my bookmarks, uninstall and reinstall.

Hi MaureenJordan, you want a white background in the toolbar area? Have you considered a theme like:

https://addons.mozilla.org/firefox/addon/white/

Adding the "white" theme makes it look like it did before. So a big THANK YOU for all who helped. I am sure others whose tabs turned black with the upgrade this week will be happy to see this fix.