Firefox Spell Checking - Add Word / Remove Words / Edit Words

Question: I just accidentally added a misspelled word to Firefox’s built in dictionary – how do I remove it?

This is a good question! Thankfully, someone at Mozilla decided the user dictionary should be stored in plain text and newline delimited. A big thank you from Chris on this one!

The only challenge is locating your Profile and then your personal / user dictionary file. The personal dictionary is called persdict.dat and lives in your Firefox Profile folder.

The Firefox Profile Folder is located in different places depending on what Operating System you are using:

• Windows XP:
  C:\Documents and Settings\%USERNAME%\Application Data\Mozilla\Firefox\Profiles\????????.default\
• Windows Vista:</br/>C:\Users\%USERNAME%\AppData\Roaming\Mozilla\Firefox\Profiles\????????.default\
• Mac OS X:
  ~/Library/Application Support/Firefox/Profiles/????????.default/
• Linux:
  ~/.mozilla/firefox/????????.default/

If you are using Windows XP or Windows Vista you can quickly jump to the directory by typing “%APPDATA%\Mozilla\Firefox\Profiles" into the run box (click on Start–>Run).

Once you have found your profile folder you need to edit the persdict.dat file. Using your favorite text editor open up that file and edit out / add in the words you desire.

You will need to restart Firefox before it will see any words you updated.