My firefox started to get really sluggish, crashing sometimes and CPU usage was way too high. It was at 30-55% the last time I checked. I have a Thinkpad T450s, so there shouldn't be any issues with performance and resources. The T450s got an i7, 12GB RAM and a 512GB SSD. I just uninstalled Firefox, downloaded the newest version and installed it. The first thing to greet me were my old tabs. Everything was like nothing happened! Every bookmark, the history and all cookies are still present. What happened?


Your personal information is stored within the following location:


When you remove and reinstall Firefox, those files and folders with your profile settings are left intact. Although you actually did successfully replace the Firefox program files, the things that you see are still retained within your Windows user profile.

I saw the same thing happen when the 64-bit version of Firefox was first released. I removed the 32-bit version of Firefox from my Windows 10 Pro x64 machine, and when I installed the 64-bit version of Mozilla's browser it made for a very smooth transition. The following information was still there:

  2. Browsing and download history
  3. Passwords
  4. Open windows and tabs
  5. Cookies
  6. Web form auto-fill information
  7. Personal dictionary

For future reference, should you need to do this again it would probably be a bit faster and easier to utilize the built-in Refresh Firefox feature, instead. In your Firefox address bar enter about:support and then select the Refresh Firefox button on the upper-right:

Refresh Firefox

Profiles - Where Firefox stores your bookmarks, passwords and other user data
Refresh Firefox - reset add-ons and settings

  • 21
    The easiest way to 'speed it up' a bit would be to navigate to about:support and click the Refresh Firefox button up the top right.
    – Bob
    Mar 28 '17 at 0:29
  • I definitely concur with @Bob's good advice. Although I rarely encounter any issues with Firefox either at work or at home, the built-in Refresh Firefox capability always seems to alleviate any lingering problems.
    – Run5k
    Mar 28 '17 at 0:34
  • I just used the Refresh function as I don't want to reinstall FF again. Thx for the help.
    – Redbeard
    Mar 28 '17 at 1:23
  • The Refresh option always works for me, although I also had speed improvements by using SpeedyFox, which is less drastic and just optimizes the profile database.
    – r41n
    Mar 28 '17 at 13:47
  • 1
    I've been using Firefox since before it was called Firefox and I never saw this option. Cool.
    – Joe
    Apr 4 '17 at 2:50

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