On Win 7 64 bit Firefox, 15, 16 and 17 beta will not save "Options" settings.
I keep up with MS and Mozilla updates. I do not remember other significant event which might have caused this problem. The advice in "http://support.mozilla.org/en-US/kb/how-to-fix-preferences-wont-save" did not help.
Additional System Details
- Next Generation Java Plug-in 10.7.2 for Mozilla browsers
- NPRuntime Script Plug-in Library for Java(TM) Deploy
- RealJukebox Netscape Plugin
- RealNetworks(tm) RealPlayer Chrome Background Extension Plug-In
- RealPlayer(tm) HTML5VideoShim Plug-In
- RealPlayer(tm) LiveConnect-Enabled Plug-In
- RealPlayer Download Plugin
- Shockwave Flash 10.3 r183
- Google Update
- McAfee MSC FF plugin DLL
- iTunes Detector Plug-in
- Adobe PDF Plug-In For Firefox and Netscape 10.1.4
- VLC media player Web Plugin 2.0.2
- The QuickTime Plugin allows you to view a wide variety of multimedia content in Web pages. For more information, visit the QuickTime Web site.
- CANON iMAGE GATEWAY Album Plugin Utility Module for IJ
- Office Live Update v1.4
- User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:17.0) Gecko/17.0 Firefox/17.0
Some more testing. Running Ff 17 Win 7. The initial response to this problem told me to delete the prefs.js files (and some similar) from my Firefox profiles. Having done that I restarted Firefox, updated my start page preference and "save downloads to" option. After a Firefox restart the "start home page" had not been saved but the download save option had. Looking at preferences saved in my profile prefs.js was empty and prefs_temp.js was full of data. So I started Firefox, updated my "start home page", looked at prefs_temp.js and it contained my updated home page option. I shutdown Firefox, checked that my update was still in prefs_temp.js, copied my prefs_temp.js to prefs.js and resterted Firefox. Square 1, the default home page displayed, not my update.
Did you try to delete both prefs files to make sure that they weren't locked or otherwise protected by security software (firewall, anti-virus)?
You can check for problems with preferences and try to rename or delete the prefs.js file and possible numbered prefs-##.js files and a possible user.js file.