How to fix preferences that won't save

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Sometimes, your Firefox optionspreferences may not be saved after you change them. For example, you may change a setting in the OptionsPreferences window only to have it set back to its previous value when you open the OptionsPreferences window again. This article may also apply if you find that after upgrading Firefox, a Firefox Updated tab opens to a page stating You’ve been updated to the latest version of Firefox every time you start Firefox. The possible causes and solutions vary depending on whether you are unable to save a few specific preferences or if no preferences save at all. Your problem might also be due to malware. See Troubleshoot Firefox issues caused by malware for more details.

Note: The Refresh Firefox feature can fix many issues by restoring Firefox to its default state while saving your essential information. Consider using it before going through a lengthy troubleshooting process.

Resetting preferences file

If you are uncomfortable performing any of the steps below, you may choose to simply reset all preferences, to see if that resolves the problem. See Reset Firefox preferences to troubleshoot and fix problems for detailed instructions. This will restore all Firefox preferences to the default state, except for any settings stored in a user.js file, if one exists.

Specific preferences are not saving

If a specific setting in Firefox keeps resetting or you are unable to change a single setting but other settings save correctly, you may have one of the following issuesthe following issue.

Third-party programs changing Firefox settings

Some programs force Firefox to use certain settings. Below is a list of programs known to do this and actions you can take to make them stop forcing Firefox settings:

  • Creative ZenCast changes Firefox's user agent, interfering with Java.
    • Uninstall the program.
  • McAfee Privacy Service turns Firefox's pop-up blocker off.
  • Norton 360 includes a "Firefox Privacy Cleanup" feature that, if enabled, overrides your Firefox Privacy settings and prevents you from keeping your Browsing History, Cookies or other private data between sessions.

Some third-party toolbars and add-ons change Firefox's home page and search settings. You can quickly reset these with the SearchReset add-on.

User.js file overriding preferences

If you don't have any of the above programs installed, or if you followed the suggestions and single preferences still aren't being saved, you You may have to edit Firefox's configuration files yourself. Don't panic, it's pretty easy. Here's how to do it.

  1. Open your profile folder:

    • Click the menu button Fx89menuButton, click Help and select More Troubleshooting Information.From the Help menu, select More Troubleshooting Information. The Troubleshooting Information tab will open.
    • Under the Application Basics section next to Profile FolderDirectory, click Open FolderShow in FinderOpen Directory. A window will open that contains your profile folder.Your profile folder will open.
    Note: If you are unable to open or use Firefox, follow the instructions in Finding your profile without opening Firefox.

  2. Click the Firefox menu Fx89menuButton and select Exit.Click the Firefox menu at the top of the screen and select Quit Firefox.Click the Firefox menu Fx89menuButton and select Quit.
  3. Open the file user.js with a text editor (like NotepadGedit or KateTextEdit).
    • If there is no user.js file, these steps won't help you.
  4. Remove the lines for the optionspreferences you want to be able to change. You can delete all the lines if you want to be able to change everything.
  5. Save the file and close the text editor.

You should now be able to change your Firefox settings.

Unable to save any preferences or settings

If none of your settings will save, if you get the Firefox Updated tab every time you start Firefox, or if you have tried the steps above with no effect, the file which Firefox uses to save your preferences may be locked or corrupted.

Locked preferences file

Firefox may be unable to save your settings if the prefs.js file (or the prefs.js.moztmp file, if it exists) is write-protected or there are other prefs backup files.

  1. Open your profile folder:

    • Click the menu button Fx89menuButton, click Help and select More Troubleshooting Information.From the Help menu, select More Troubleshooting Information. The Troubleshooting Information tab will open.
    • Under the Application Basics section next to Profile FolderDirectory, click Open FolderShow in FinderOpen Directory. A window will open that contains your profile folder.Your profile folder will open.
    Note: If you are unable to open or use Firefox, follow the instructions in Finding your profile without opening Firefox.

  2. Click the Firefox menu Fx89menuButton and select Exit.Click the Firefox menu at the top of the screen and select Quit Firefox.Click the Firefox menu Fx89menuButton and select Quit.
  3. Locate the prefs.js file (and, if present, the prefs.js.moztmp file).
  4. Right click on each file in turn and select Properties from the context menu. Check that under Attributes, there is no check in the box next to Read Only for either file.
    • If RealPlayer is open, that may be locking the prefs.js file. Closing RealPlayer should unlock it.
  5. Delete any prefs-n.js files where n is a number (e.g. prefs-2.js).
  6. Delete Invalidprefs.js if it exists.
  7. Restart Firefox. You should now be able to save preferences.
  1. Open your profile folder:

    • Click the menu button Fx89menuButton, click Help and select More Troubleshooting Information.From the Help menu, select More Troubleshooting Information. The Troubleshooting Information tab will open.
    • Under the Application Basics section next to Profile FolderDirectory, click Open FolderShow in FinderOpen Directory. A window will open that contains your profile folder.Your profile folder will open.
    Note: If you are unable to open or use Firefox, follow the instructions in Finding your profile without opening Firefox.

  2. Click the Firefox menu Fx89menuButton and select Exit.Click the Firefox menu at the top of the screen and select Quit Firefox.Click the Firefox menu Fx89menuButton and select Quit.
  3. Locate the prefs.js file (and, if present, the prefs.js.moztmp file).
  4. For each file, make sure that your user has write permissions to the file.
  5. Delete any prefs-n.js files where n is a number (e.g. prefs-2.js).
  6. Delete Invalidprefs.js if it exists.
  7. Restart Firefox. You should now be able to save preferences.
  1. Open your profile folder:

    • Click the menu button Fx89menuButton, click Help and select More Troubleshooting Information.From the Help menu, select More Troubleshooting Information. The Troubleshooting Information tab will open.
    • Under the Application Basics section next to Profile FolderDirectory, click Open FolderShow in FinderOpen Directory. A window will open that contains your profile folder.Your profile folder will open.
    Note: If you are unable to open or use Firefox, follow the instructions in Finding your profile without opening Firefox.

  2. Click the Firefox menu Fx89menuButton and select Exit.Click the Firefox menu at the top of the screen and select Quit Firefox.Click the Firefox menu Fx89menuButton and select Quit.
  3. Locate the prefs.js file (and, if present, the prefs.js.moztmp file).
  4. For each file, hold down the Ctrl key as you click on the file then select Get Info.
  5. Make sure that the Locked option is unchecked.
  6. Delete any prefs-n.js files where n is a number (e.g. prefs-2.js).
  7. Delete Invalidprefs.js if it exists.
  8. Restart Firefox. You should now be able to save preferences.

Corrupt preferences file

The preferences file may be corrupt, preventing Firefox from writing to it. If you delete this file, Firefox will automatically create another one when it needs to.

Here's how to delete the prefs.js file.

This will remove all your custom settings and settings for many extensions.
  1. Open your profile folder:

    • Click the menu button Fx89menuButton, click Help and select More Troubleshooting Information.From the Help menu, select More Troubleshooting Information. The Troubleshooting Information tab will open.
    • Under the Application Basics section next to Profile FolderDirectory, click Open FolderShow in FinderOpen Directory. A window will open that contains your profile folder.Your profile folder will open.
    Note: If you are unable to open or use Firefox, follow the instructions in Finding your profile without opening Firefox.

  2. Click the Firefox menu Fx89menuButton and select Exit.Click the Firefox menu at the top of the screen and select Quit Firefox.Click the Firefox menu Fx89menuButton and select Quit.
  3. Locate the prefs.js file (and, if present, the prefs.js.moztmp file).
  4. Delete those files and any prefs-n.js files where n is a number (e.g. prefs-2.js).
  5. Delete Invalidprefs.js if it exists.
  6. Restart Firefox. You should now have all your preferences reset.



Based on information from Preferences not saved (mozillaZine KB)