All of the changes you make in Firefox, like your home page, what toolbars you use, saved passwords and your bookmarks, are all stored in a special folder, called a profile. Your profile folder is stored in a separate place from the Firefox program so that, if something ever goes wrong with Firefox, your information will still be there. It also means you can uninstall Firefox without losing your settings and you don't have to reinstall Firefox to clear your information or troubleshoot a problem.

How do I find my profile?

1. At the top of the Firefox window, click on the Firefox button, go over to the Help menuOn the menu bar, click on the Help menuAt the top of the Firefox window, click on the Help menu and select Troubleshooting Information. The Troubleshooting Information tab will open.Click the menu button , click help and select Troubleshooting Information. The Troubleshooting Information tab will open.

2. Under the Application Basics section, click on Show FolderShow in FinderOpen Directory. A window with your profile filesfolder will open.
Note: If you are unable to open or use Firefox, follow the instructions in Finding your profile without opening Firefox.

Finding your profile without opening Firefox

What information is stored in my profile?

• Passwords: Your passwords are stored in the key3.db and signons.sqlitelogins.json files. For more information, see Password manager - Remember, delete and change saved passwords in Firefox.
• Site-specific preferences: The permissions.sqlite and content-prefs.sqlite files store many of your Firefox permissions (for instance, which sites are allowed to display popups) or zoom levels that are set on a site-by-site basis. For more information, see Permissions Manager - Give certain websites the ability to store passwords, set cookies and more and Font size and zoom - increase the size of web pages.
• Search engines: The search.sqlite file and searchplugins folder store the search engines that are available in the Firefox Search bar.
• Personal dictionary: The persdict.dat file stores any custom words you have added to Firefox's dictionary. For more information, see How do I use the Firefox spell checker?.
• Autocomplete history: The formhistory.sqlite file remembers what you have searched for in the Firefox search bar and what information you’ve entered into forms on websites. For more information, see Control whether Firefox automatically fills in forms with your information.

• Cookies: A cookie is a bit of information stored on your computer by a website you’ve visited. Usually this is something like your site preferences or login status. Cookies are all stored in the cookies.sqlite file.
• DOM storage: DOM Storage is designed to provide a larger, more secure, and easier-to-use alternative to storing information in cookies. Information is stored in the webappsstore.sqlite file for websites and in the chromeappsstore.sqlite for about:* pages.
• Security certificate settings: The cert8.db file stores all your security certificate settings and any SSL certificates you have imported into Firefox.
• Security device settings: The secmod.db file is the security module database.
• Download actions: The mimeTypes.rdf file stores your preferences that tell Firefox what to do when it comes across a particular type of file. For example, these are the settings that tell Firefox to open a PDF file with Acrobat Reader when you click on it. For more information, see Change what Firefox does when you click on or download a file.
• Plugin MIME type: The pluginreg.dat file stores Internet media types related to your installed plugins. For more information, see Use plugins to play audio, video, games and more.
• Stored session: The sessionstore.js file stores the currently open tabs and windows. For more information, see Restore previous session - Configure when Firefox shows your most recent tabs and windows.

• User preferences: The prefs.js file stores customized user preference settings, such as changes you make in Firefox OptionsPreferences dialogs. The optional user.js file, if one exists, will override any modified preferences.
• User styles: If they exist, the \chrome\userChrome.css and \chrome\userContent.css files store user-defined changes to either how Firefox looks, or how certain websites or HTML elements look or act.

Working with profiles

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

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

• Use the Profile Manager to create and remove Firefox profiles explains how to do things like create a new profile and delete an old one.
• Back up and restore information in Firefox profiles explains how to back up and restore a profile. It also explains how to move your profile information to a different location on your hard drive or to another computer.
• Recovering important data from an old profile describes what information is stored in each of the files in your profile and explains how to copy them to a new profile.