Mozilla is planning to add a 'reset' button to Firefox. The idea is to enable users to repair their Firefox install or revert to a default state, while also retaining their data, bookmarks, history and so on. Work is underway on implementing the feature, which will be accessible in several ways.
"There are a number of serious Firefox issues (not starting, crashing, unexpected behavior, lost toolbars and more) that can be solved by creating a new profile," the Mozilla wiki page dedicated to the new feature reads
"The problem is, creating a new profile (which is an incredibly difficult task) is not enough. A user will almost always want to also migrate their data to the new profile which is another difficult task," it says.
Firefox, just like any other software, can run into problems that can't be fixed, or can't be fixed easily enough, without starting with a clean slate.
The problem is, unless users also delete their profile folders manually, if they even know they exists, simply reinstalling Firefox doesn't really fix things.
What is needed is a way of wiping all of the settings data, add-on settings and so on, while still enabling users to retain their personal data. There is still some discussion on what to keep and what to delete.
"Many users try to reinstall Firefox to solve these issues but reinstallation doesn't do anything to the profile folder. Providing this option upon reinstallation and, in addition, offering this after consecutive start-up crashes and on the Troubleshooting Information page will make this feature both intuitive and discoverable," Mozilla explains.
The solution is to provide a 'reset' option. Mozilla is working on building it into the installer. This way, when users want to reinstall Firefox, they'll also get the option to delete all data, except their personal one. But this only works on Windows, there is no installer on Mac OS X or Linux.
The second method would be built into Firefox. The browser would detect consecutive startup crashes and, after three attempts, offer users the option of resetting the preferences and so on. Finally, there will also be a Reset Firefox button in the browser's Troubleshooting information page.
The Reset Firefox feature is still under development and no clear Firefox version target has been set, so it may be a while before you see it working.