That is incredibly annoying. I assume when you were in about:config you were able to save your changes there. If the preferences cannot be changed and/or have a status of "locked" we'll point you toward some other areas of investigation.

Has this been going on for a while, long enough that you have already shut down and restarted Windows? Occasionally after Windows updates users have reported permission glitches affecting Firefox, and those are fixed by shutting down and restarting Windows.

Most settings changes in Options and in about:config are stored in a file named prefs.js. Sometimes Firefox can't save changes to that file, or external software takes over the file and reverts your changes. The following article has suggestions for investigating/fixing this: How to fix preferences that won't save. If you use Advanced SystemCare, or your security software has a browser settings protection feature, try disabling those features until you have your Firefox settings the way you want them.

You can check for problems with preferences.

Delete possible user.js and numbered prefs-##.js files and rename (or delete) the prefs.js file to reset all prefs to the default value including prefs set via user.js and prefs that are no longer supported in current Firefox releases.

• http://kb.mozillazine.org/Preferences_not_saved
• http://kb.mozillazine.org/Resetting_preferences

First let me thank both jscher2000 & cor-el for their time to try to help me. Also, I and not really tech savvy or that experienced so its hard for me to read tech articles/information and fully understand what it is that I supposed to do. So, I really need very specific help. That being said, I think I found the problem in about:config. I think these two lines are causing the problem... browser.usedOnWindows10;true  ; with status as "user set" and type as "boolean", and the other line is browser.usedOnWindows10.introURL;https://www.mozilla.org/%LOCALE%/firefox/windows-10/welcome/?utm_source=firefox-browser&utm_medium=firefox-browser  ; with status as "default" and type as "string". That https command without "/%LOCALE%" is the "Firefox + Windows 10. Perfect Together" page. However, when I change "true" to "false" and/or delete the https string neither change is saved when I close Firefox and restart Firefox and that annoying page opens again. Also, I have been having this problem since I upgraded to Windows 10 on my computer, about two months ago. Finally, I'm not sure I understood the articles/links you guys attached to your comments about the "prefs" and/or "user" files; which I found in two different places. Would it be helpful if I sent you a copy of what those files have in them. Also, in one place there is a prefs file with info in it; and then also prefs files that look like prefs-1 through prefs-3686, with no info in them and read-only which I removed the read-only from all these files. These files are found in "C:\ProgramData\Kaspersky Lab\SafeBrowser\S-1-5-21-2269593390-3903269557-3519354090-1002\FireFox". There is also a prefs file (one only) and user file in "C:\Users\Burt\AppData\Roaming\Mozilla\Firefox\Profiles\qoqmorm0.default-1426175604250". Is any of what I just sent helpful at all? If you need more info or need me to sent you what's in the prefs and/or user file let me know. Again, thanks for all your help. Burt

Hi Burt, I'm not sure what all those files are doing in the Kaspersky folder. If you look at the dates, are they recent? Could Kaspersky be backing them up and then zapping your main file in your Firefox profile folder?? It's rather puzzling...

Try to delete the prefs.js file in the qoqmorm0.default-1426175604250 folder if that is the current profile folder (1426175604250 would suggest that you have reset Firefox on March 12).

You can use this button to go to the current Firefox profile folder:

• Help > Troubleshooting Information > Profile Directory: Show Folder (Linux: Open Directory; Mac: Show in Finder)
• http://kb.mozillazine.org/Profile_folder_-_Firefox

Delete possible user.js and numbered prefs-##.js files and rename (or delete) the prefs.js file to reset all prefs to the default value including prefs set via user.js and prefs that are no longer supported in current Firefox releases.