No idea/ and 56.0.2 is no longer supported due to security risks possibly like what that maybe. Where did you get the file to reinstall ?

Check your add/remove programs for anything unusual.

Please use more than 1 scanner as each uses diff tech : https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-caused-malware Save your Report and google each before deleting anything as do not want to delete something you need, If need help : https://forums.malwarebytes.com/topic/9573-im-infected-what-do-i-do-now/ Post in only 1 forum, then wait.

Unfortunately 56.0.2 is no longer safe to use for every day use, do to security issues, but 52.5.0 ESR is. It will continue to get security updates until May 2018, and you can download and install it from this page: https://www.mozilla.org/en-US/firefox/organizations/all/ Note : Legacy Extensions will be deleted or removed in any version update after May 2018.

You should make a backup of your Profile before going back and just because: https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles

Going back is not good idea if have new cpu.

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

I re-installed 56.0.2 from https://ftp.mozilla.org/pub/firefox/releases/56.0.2/

I'll try the older 52.5.0 ESR version in a few days when I have more time to spend on this issue.

FWIW, when I click on that useless orange widget I get a list of actions that makes it obvious that it is a half-assed attempt to replace the menubar. I have the "classic theme restorer" extension installed precisely to restore the menubar after someone made the ill-advised decision to remove that functionality from FireFox a long time ago.

Do you mean the "firefox button" thing in the very to left corner? That button has been in the browser for a long time.

But! Since you have gone back to the old version of FF, and you have access to Classic Theme Restorer. I see you already have it. Open the options in the theme restorer and go to the options for the Firefox button. I can't provide you with pictures because I'm on 57 now. But, you should be able to find what you want, and customize the button to your liking with the theme restorer. You can change it's color/size/style, and I believe you can remove it entirely.

Being fair. I never used the FF button either, and it seems gone in 57. 57 is a mix of good, and bad.

Note that this button is part of the Classic Theme Restorer extension that appears in your System Details list.

You can check the Options/Preferences of CTR in about:addons.

• "3-bar" menu button or Tools -> Add-ons -> Extensions

RobStow said

... I have the "classic theme restorer" extension installed precisely to restore the menubar after someone made the ill-advised decision to remove that functionality from FireFox a long time ago.

That's silly! The Menu Bar was never removed, just hidden by default. As of Firefox 29 all a person needs to do is to hit the Alt key to display the Menu Bar (temporarily), then open the View menu, open Toolbars, and select Menu Bar to have it showing all the time.

Or leave it hidden for a smaller UI and more room for page content and when you need the Menu Bar to access one of those menus simply hit the Alt key.