Sometimes a problem with Firefox may be a result of malware installed on your computer, especially changes that are occurring without your permission, like your search engine. You can try these free programs to scan for malware, which work with your existing antivirus software [Note, not all spyware scanners will find everything so you may have to try a couple to get it nailed down]: * [https://www.microsoft.com/en-us/wdsi/products/scanner Microsoft Safety Scanner] * [http://www.malwarebytes.org/products/malwarebytes_free/ MalwareBytes' Anti-Malware] * [http://support.kaspersky.com/viruses/disinfection/5350 Anti-Rootkit Utility - TDSSKiller] (for more info, see this [https://www.bleepingcomputer.com/download/tdsskiller/ alternate TDSSKiller download page]) * [https://www.malwarebytes.com/adwcleaner/ AdwCleaner] (for more info, see this [http://www.bleepingcomputer.com/download/adwcleaner/ alternate AdwCleaner download page]) * [http://www.surfright.nl/en/hitmanpro/ Hitman Pro] * [http://www.eset.com/us/online-scanner/ ESET Online Scanner] Further information can be found in the [[Troubleshoot Firefox issues caused by malware]] article. Did this fix your problems? Please report back to us!

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.