Did you know that all the settings you make in Firefox, like your home page, what toolbars you use, saved passwords and bookmarks are all stored in a special profile folder? It's true. Your profile folder is kept 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?

• Click the menu button , 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.

Finding your profile without opening Firefox

What information is stored in my profile?

• Bookmarks and Browsing History: The places.sqlite file contains all your Firefox bookmarks and the list of all the websites you’ve visited. For more information, see Bookmarks in Firefox.
• Passwords: Your passwords are stored in the key3.db and signons.sqlite 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 (e.g 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.
• Download history: The downloads.sqlite file remembers what you have downloaded. For more information, see Where to find and manage downloaded files in Firefox.
• 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 Manage file types and download actions in Firefox.
• 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.
• Toolbar customization: The localstore.rdf file stores toolbar and window size/position settings. For more information, see Customize Firefox controls, buttons and toolbars.
• 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 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.
• Profile Manager - Create, remove or switch 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.