I mistakenly added an errant misspelling to the windows version Firefox custom dictionary.

How can I find and remove this word?

2 Answers 2


Windows or Linux?

In windows, open the Appdata folder in your user profiles (%appdata% for easy access). Go to Mozilla, Firefox, Profiles, then click your profile. There should be a file called "persdict.dat", open it in notepad and find your misspelled word and delete it. Save the file, restart firefox and you're good!

In linux it's the same deal, except go to your ~ directory instead of appdata.

Make sure to exit Firefox beforehand, or else it will overwrite your edits.

  • In Windows ....
    – WilliamKF
    Feb 1, 2011 at 18:20
  • You must exit Firefox before editing or Firefox will overwrite your edits.
    – WilliamKF
    Feb 1, 2011 at 18:27

From this article in Life hacker: link

  1. Open your application data folder. On XP or Vista, go to your Start menu and hit Run (or just press Windows-R) and paste in %APPDATA%\Mozilla\Firefox\Profiles; on your Mac, navigate to ~/Library/Application Support/Firefox/Profiles.
  2. Find your profile folder, which by default should look something like xxxxxxxx.default.
  3. Inside your profile folder, find the file called persdict.dat and open it up in your text editor of choice.
  4. Now just find the misspelling, delete it, and you're done.

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