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. 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.

Well,thanks. But I have already refreshed it twice.

Sorry,the picture failed to upload.

Hello Soapere,

KeyPass Tusk does have the "Add to Firefox" button :

https://addons.mozilla.org/en-US/firefox/addon/keepass-tusk/

Your system details show that you have two very suspious looking extensions installed :

Addons Manager 3.61.1 (cpmanager@mozillaonline.com) and Firefox Homepage 3.62 (cehomepage@mozillaonline.com)

They just might be the cause - would you please remove them  ?

It might be a good idea to run some malware scans, as listed in this article :

https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-caused-malware

(better safe than sorry ..... )

Is the "Add to Firefox" button back  ?

Note that @mozillaonline.com extensions are possibly part of a Chinese Firefox version (mozillaonline.com redirects to www.firefox.com.cn).

Start Firefox in Safe Mode to check if one of the extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) or if hardware acceleration is is causing the problem.

• switch to the DEFAULT theme: "3-bar" menu button or Tools -> Add-ons -> Appearance
• do NOT click the "Refresh Firefox" button on the Safe Mode start window

• https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode
• https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems

You can also check for issues caused by your Kaspersky security software.