Reset Firefox – easily fix most problems. https://support.mozilla.org/en-US/kb/re ... t-problems
If you're having problems with Firefox, resetting it can help. The reset feature fixes many issues by restoring Firefox to its factory default state while saving your essential information like bookmarks and open tabs.
What does the reset feature do?
All of your Firefox settings and personal information are stored in a profile folder. The reset feature works by creating a new profile folder for you while saving your important data.
Firefox will save these things:
- Bookmarks
- Browsing history
- Passwords
- Open windows, tabs and tab groups
- Cookies
- Web form auto-fill information
- Personal dictionary
These items and settings will be removed:
Extensions and themes, website-specific preferences, search engines, download history, DOM storage, security settings, download actions, plugin settings, toolbar customizations, user styles and social features will be removed.
Note: Your old Firefox profile will be placed on your desktop in a folder named "Old Firefox Data." If the reset didn't fix your problem you can restore some of the information not saved by copying files to the new profile that was created. If you don't need this folder any longer, you should delete it as it contains sensitive information.