Mozilla has made Firefox a very user friendly and modular web browser. It’s currently the browser in which all others are compared, and for very good reasons. With that, I’ll step down from my soapbox to answer the question at hand:

How does one easily reset the preferences of Firefox?

philf: is there a way to ‘restore” to a previous days setting? all of a sudden firefox won’t open a site that requires flash [site removed] when trying to use it just a blue screen. I’ve had this issue before, I can’t remember how I fixed it, it was working yesterday perfectly. ALSO firefox used to open the previous tabs when closed, now just a blank screen..I didn’t do anything to it yesterday no updates at all…

This won’t exactly answer the question asked from the quoted IRC text, but as far as I know there isn’t a “snapshot” type service that can restore Firefox to a previous day’s settings. I would be surprised if someone hadn’t made a plugin for this scenario yet. What follows is an “all else fails” solution to just restore a default set of options in which to start over.

To paraphrase Mozilla’s own instructions:

  1. Exit from Firefox completely (after copying/printing these instructions of course)
  2. Locate your profile folder. This will probably be the most difficult step for new users as it lies within a “hidden” folder in your home folder. I’ll explain a little later.
  3. Rename and/or remove your prefs.js file. Think safety first: rename now, remove later when clearly not needed.
  4. Restart Firefox.

Firefox will rebuild the prefs.js upon restart to its default state. Some users may also have a user.js file which may or may not cause some issues. It’s not a default file and could possibly have been made by a plugin or another installed application. My user.js file was created for and by Google’s Picasa. Rename/remove it as well if you’re still experiencing issues.

The strategy of renaming a settings file is to ensure that you still have a copy in case you need it. Any time I find myself tweaking files, I will make a backup copy of it first (cp file file.bu). In the case of Firefox, we only need to rename it in order to force Firefox to save a new default file. We can always restore the original file be deleting the new one and renaming the original.

Your Firefox profile folder is contained in a folder named .mozilla that is hidden from normal viewing because of it’s leading dot or period. While viewing your home folder in nautilus’s file browser, you can use CTRL-H to show all hidden files. Open .mozilla then firefox. Within you should see a folder ending in .default. The first eight letters are randomly chosen for you when Firefox is first run. That’s your Firefox profile folder. Open that and you should see the prefs.js file. Continue with step 3 above.

Remember that within the profile folder is everything that Firefox knows about you including saved passwords and cookies. If you accidentally change the wrong file, you could prevent yourself from accessing certain websites.

  • Share/Bookmark