Any browser can slow down and become cluttered over time as you install add-ons, build up history, and change settings. Firefox can “Refresh” your profile to quickly give you a clean slate while keeping your most important data. This would let you try the overhauled Firefox Quantum with a fresh profile, speed Firefox up if it’s become slow, or fix other browser problems.
What This Keeps, and What It Removes
The “Refresh” feature won’t delete everything. Firefox will keep your bookmarks and saved passwords. You’ll be prompted if you want to reopen your currently open tabs after the Refresh, too, so you won’t even lose your open tabs.
However, this will delete your installed add-ons and erase all their locally stored data. It will also reset your browser settings to their default values and clear the browser history and other cached data.
This ensures any problems caused by misbehaving extensions or issues with Firefox’s settings will be fixed by this process, speeding a slow Firefox up and fixing other problems. However, your important personal data will be kept—with the exception of any browser extensions and their data.
How to Refresh Firefox
To do this, click the menu button at the top right corner of the Firefox window.
Click the “Help” option near the bottom of the menu.
Click the “Troubleshooting Information” option in the Help menu.
Click the “Refresh Firefox” button at the top right corner of the Troubleshooting Information page.
You’ll be warned that this will remove your browser add-ons, reset your customizations, and revert other browser data to the default settings. Click “Refresh Firefox” to confirm you want to make these changes.
Firefox will close while it clears away the old data. After a few moments, it will reopen with a fresh browser and ask if you want to restore the tabs you had open before it closed.