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Possibly corrupt prefs.js file. Need help with this file please.


I've been having a problem with sending/receiving text messages in Yahoo Messenger and I think I've narrowed it to the prefs.js file in Firefox. I'm using Firefox 3.6.25 on Windows XP sp3. The Yahoo Messenger window would not open when the appropriate mobile phone link was clicked. I uninstalled/reinstalled flash without change. I cleared cache, etc., without change. I created a new Firefox profile and I was able to get the Yahoo Messenger window to open. When I copied the prefs.js file from the old profile to the new profile, I encountered the problem again. I opened the prefs.js file with wordpad and noticed that editing should occur in about:config in the currently running Firefox browser. I briefly compared the two about:config tabs from the working profile and the non-working profile. They were significantly different. How do I make a copy of one so that I can paste it into wordpad and make the editing of the other one easier? Where can I find information about the individual parameters and their settings?

Additional System Details

This happened

Every time Firefox opened

Installed Plug-ins

  • Adobe PDF Plug-In For Firefox and Netscape
  • Default Plug-in
  • NPRuntime Script Plug-in Library for Java(TM) Deploy
  • BrowserPlus -- Improve your browser! -- http://browserplus.yahoo.com/
  • Shockwave Flash 11.2 r202
  • Adobe Shockwave for Director Netscape plug-in, version
  • Windows Presentation Foundation (WPF) plug-in for Mozilla browsers
  • Npdsplay dll
  • DRM Store Netscape Plugin
  • DRM Netscape Network Object


  • User Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv: Gecko/20111212 Firefox/3.6.25 (.NET CLR 3.5.30729)

More Information

  • Top 10 Contributor
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10738 solutions 96600 answers

You can check the mailto prefs if the problem is with an email program (on about:config -> Filter: mailto).

Question owner

The two about:config tabs were significantly different. The one that belonged to the non-working profile was missing a significant number of parameters. The mailto parameter may be inaccurate or corrupt but I would like to have access to all of the parameters and their functions so that I can return my profile to how I previously set it.

Modified by aqualion

  • Top 10 Contributor
  • Moderator
10738 solutions 96600 answers

Probably only print prefs that haven't been initialized and prefs added by extensions are missing.
There may be some prefs that are normally hidden if they have a default value that you do not see on the about:config page and there may also be prefs from older Firefox versions that are now obsolete and no longer supported that are not needed anymore.
The prefs.js file only stores prefs that show bold, user set, on the about:config page.