Private or anonymous browsing can be useful in a lot of cases, especially if you’re using public workstations, sharing your PC with someone, need to perform some confidential tasks, etc. It can be a good habit to always launch your browser in private mode manually, since almost all major internet browsers now support this feature. However, you never know when you may forget to turn on anonymous browsing and compromise your privacy.
For all such instances, it can be really helpful if you set the browser to automatically, always start in private mode. If you’re using Firefox, this little hack will do the trick.
Launch Firefox, enter about:config in the URL bar and hit enter. The browser will prompt with a warning, promise to be careful and you’ll get Firefox’s advanced preferences screen.
The string you’re looking for here is browser.privatebrowsing.autostart. Enter the text in filter box to get only this result, or scroll down the page till your get the desired string. The default value is set to false. Just double-click the test and its value will change to true. Close the browser, and the next time you start Firefox, it will not keep any record of your browsing history.
Update: There is a more easier method which doesn’t require any configuration. Simply go to Options and navigate to Privacy Tab. Now select “Use custom settings for history” from dropdown and check private browsing as shown in the screenshot below.
We tested this hack on Firefox 3.6.4.