Hi, hold down the Shift key when you start Firefox to start in Safe Mode. More - Diagnose Firefox issues using Troubleshoot Mode.

If it works in Safe Mode, disable any theme or add-ons you have - Add-ons Manager (Ctrl+Shift+A) > Themes/Extensions and restart Firefox; then if it's OK, re-enable them one by one until you find the culprit. You may need to restart Firefox after enabling some add-ons.

If that doesn't help, I'm going to suggest you try Refresh, but since it can very occasionally cause issues of its own - to be on the safe side, before you do it, I would backup your bookmarks: Open bookmarks > Show All Bookmarks > Import and Backup > Backup. Or, Export Bookmarks to HTML, and save them to somewhere convenient on your computer. Note that Backup will overwrite any existing bookmarks when you restore them. For extra safety, I'd suggest making both a Backup - which creates a JSON file, and an HTML file. You can instead backup all your data by copying your Profile, but this requires some technical expertise - Back up and restore information in Firefox profiles.

The Refresh feature (called "Reset" in older Firefox versions) can fix many issues by restoring Firefox to its factory default state while saving your bookmarks, history, passwords, cookies, and other essential information.

Note: When you use this feature, you will lose any extensions, toolbar customizations, and some preferences so you might want to make a note of any add-ons. See the Refresh Firefox - reset add-ons and settings article for more information.

To Refresh Firefox:

1. Open the Troubleshooting Information page using one of these methods:
   • Click the menu button , click help and select Troubleshooting Information. A new tab containing your troubleshooting information should open.
   • If you're unable to access the Help menu, type about:support in your address bar to bring up the Troubleshooting Information page.
2. At the top right corner of the page, you should see a button that says "Refresh Firefox" ("Reset Firefox" in older Firefox versions). Click on it.
3. Firefox will close. After the refresh process is completed, Firefox will show a window with the information that is imported.
4. Click Finish and Firefox will reopen.

Did this fix the problem? Please report back to us!

Thank you.

Me too: I just want to copy the URL, could yesterday, today right click opens the URL instead. Can't find any reply other than "reset" or "safe mode" which are useless.

I found a fix, at least so far it is working perfectly. It was posted by RAM 'in answering a post "New Tab Not Working!" 10/14/17. Bob W Here is what he had said:

If you have tried all these and is still not working then you try the steps below-

1) Go to the root folder where Firefox is installed

it is generally installed in C:\Program Files\Mozilla Firefox)

2) Right-click Firefox- properties-details tab and click on Remove properties and personal information-just click ok 3) now a new firefox - Copy.exe is created

 use the new one as your default browser

I hope this helps

Modified October 14, 2017 at 6:48:49 AM PDT by ram