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Privacy in Firefox

To improve your experience on the internet, Firefox stores a collection of data relevant to the sites you visit.  For example, Firefox stores the following things as you browse:

  • Visited page history: This allows you to go back to sites you've visited, find them using the Smart Location Bar and see them in both the History menu, History sidebar and library window.
  • Form and Search Bar entries: This remembers what you've filled out in the search bar and on forms on pages to make filling the same forms and performing the same searches easier.
  • Logins and passwords: This makes it easier to log in to frequently visited sites.
  • Download list: This helps you find files you previously downloaded.
  • Cookies: Cookies are small bits of information that sites use to save site preferences and sessions so they can identify you between visits (and remember things like your shopping cart or keep you logged in).
  • Web cache: A cache stores pages and other web content that you've already seen so that Firefox can use the stored content rather than having to download it again, greatly speeding up browsing and reducing demands on web servers.  By default, this is not stored for secure (https) websites to avoid retaining secure data.
  • Browsing sessions: This allows Firefox to restore the tabs you had open when you start it or after a crash.
In general, these can optimize your browsing experience and are very useful.  However, in specific instances, you may not want to save this information.  For example, you may be using another person's computer or visiting sites with sensitive information.  You may also need to remove previously stored data if websites mis-identify you.  Firefox 3.5 offers many ways to control what information is stored and prevent it from being stored when you don't want it.

Private Browsing


Firefox 3.5 has a mode called Private Browsing where none of the above information is saved until Private Browsing is turned off.

Starting Private Browsing session:

  1. Click on the Tools menu and select Start Private Browsing.
    • The first time you turn on Private Browsing, Firefox will alert you that it will save your current windows and tabs for after you finish using Private Browsing. Click on Start Private Browsing to continue.
  2. You will then enter Private Browsing mode, and the Private Browsing information screen will appear.
When browsing in Private Browsing mode, the Firefox window title will show (Private Browsing) during your session.

Turning off Private Browsing

To end a Private Browsing session:
  1. Click on the Tools menu and select the Private Browsing entry , which will show a check mark to indicate that Private Browsing is currently enabled.
  2. The windows and tabs you were using when you enabled Private Browsing will appear, and you can use Firefox normally.
    • The Firefox window's title will no longer show (Private Browsing) when Private Browsing is off. Firefox will restore your windows.

Clear Recent History

If you did not use Private Browsing and want to retroactively delete saved information from earlier Firefox sessions, you can use the Clear Recent History feature.

  1. Go to Tools > Clear Recent History or press Ctrl+Shift+Del
    • The Clear Recent History dialog box appears.
  2. Select the time range to clear at the top of the dialog.  You can choose how far back you want to remove, or choose Everything.

  3. Press the Details arrow to show the types of data to clear.

    You can choose which kinds of data you'd like to remove.  For example, to remove browsing history, select Browsing & Download History. Site Preferences refers to site-specific browser settings such as the zoom level and whether you've enabled cookies or images on the site.

    Caution: Be sure to remove checks in the remaining check boxes for any private data that you do not want to be cleared!
  4. Verify your selections then click Clear Now. 

Removing information for a specific website

Firefox can also remove all stored information for a specific website:

  1. From History menu, select Show All History.
  2. Type the name of the website in the Search History field, and press Enter.
  3. From the results, right-click on the site you wish to clear, and select Forget About This Site.