https://support.mozilla.org/en-US/kb/how-to-fix-preferences-wont-save

Note: Some software, like Advanced SystemCare with Surfing Protection, can protect files in the Firefox profile folder against changes. If you have such software then check the settings or uninstall this software.

A detail like a website remembering you (log you in automatically) is stored in a cookie.

You can use these steps to make a website recognize and remember you:

• You can create a cookie "Allow" exception to keep specific cookies, especially in case of secure websites and when cookies expire when Firefox is closed.
• Tools > Options > Privacy > "Use custom settings for history" > Cookies: Exceptions

In case you use "Clear history when Firefox closes" or otherwise clear history.

• do not clear the Cookies
• do not clear the Site Preferences

• Tools > Options > Privacy > Firefox will: "Use custom settings for history": [X] "Clear history when Firefox closes" > Settings
• https://support.mozilla.org/kb/remove-recent-browsing-search-and-download-history

• clearing "Site Preferences" clears exceptions for cookies, images, pop-up windows, and software installation and exception for password and other website specific data
• clearing cookies will remove all selected cookies including cookies with an "Allow" exception you may want to keep

FredMcD said

https://support.mozilla.org/en-US/kb/how-to-fix-preferences-wont-save Note: Some software, like Advanced SystemCare with Surfing Protection, can protect files in the Firefox profile folder against changes. If you have such software then check the settings or uninstall this software.

I followed the suggestions at the link you provided, specifically at the one section "Unable to save any preferences or settings". I did the steps that involved locating the prefs.js file (I couldn't locate a prefs.js.moztmp file). I followed each of the steps, restarted Firefox and was still unable to save preferences/settings.

cor-el said

A detail like a website remembering you (log you in automatically) is stored in a cookie. You can use these steps to make a website recognize and remember you:

• You can create a cookie "Allow" exception to keep specific cookies, especially in case of secure websites and when cookies expire when Firefox is closed.
• Tools > Options > Privacy > "Use custom settings for history" > Cookies: Exceptions

In case you use "Clear history when Firefox closes" or otherwise clear history.

• do not clear the Cookies
• do not clear the Site Preferences

• Tools > Options > Privacy > Firefox will: "Use custom settings for history": [X] "Clear history when Firefox closes" > Settings
• https://support.mozilla.org/kb/remove-recent-browsing-search-and-download-history

• clearing "Site Preferences" clears exceptions for cookies, images, pop-up windows, and software installation and exception for password and other website specific data
• clearing cookies will remove all selected cookies including cookies with an "Allow" exception you may want to keep

The problem I'm having isn't with cookies, I don't think. It's that Firefox won't remember my settings in the Privacy and Security sections. I set them to remember my search history, saved logins/passwords, etc. Firefox will then remember these settings until I log off my computer. When I turn my computer again I check and find that Firefox hasn't saved my settings in Privacy and Security. I never had this problem until just a few days ago so I don't know what could have happened that would change this.

Are you using any of these?

Note: Some software, like Advanced SystemCare with Surfing Protection, can protect files in the Firefox profile folder against changes. If you have such software then check the settings or uninstall this software.

What are you using as your protection programs?

trend micro password manager that may be part of this security suite can be responsible for that behaviour. please uninstall it through your system control panel in case you're not using that piece of software.

FredMcD said

Are you using any of these?

Note: Some software, like Advanced SystemCare with Surfing Protection, can protect files in the Firefox profile folder against changes. If you have such software then check the settings or uninstall this software.

What are you using as your protection programs?

I have TrendMicro. I just saw Phillip's suggestion below and tried that (completely uninstalling the TrendMicro Password Manager, instead of just not using it) and that worked! Thanks to you and everyone here who helped me with suggestions, I really appreciate it.

philipp said

trend micro password manager that may be part of this security suite can be responsible for that behaviour. please uninstall it through your system control panel in case you're not using that piece of software.

Thank you so much! Your suggestion worked perfectly. Firefox now remembers my privacy and security settings. I would have never thought that the TrendMicro Password Manager was the problem because I had never used it. But I had never uninstalled it either. Once I uninstalled it and then restarted my computer my Firefox security and privacy settings were saved. Thanks again for your help, I really appreciate it.

Great News Safe Surfing

I am not using Trendmicro or any other password manager but have the same problem with username and password information being lost after shutting down my computer. The information is saved however between closing firefox and restarting it. Are there any other issues or software interactions that could cause this?

https://support.mozilla.org/en-US/kb/how-to-fix-preferences-wont-save

Note: Some software, like Advanced SystemCare with Surfing Protection, can protect files in the Firefox profile folder against changes. If you have such software then check the settings or uninstall this software.