As you know to fix the problems such as slowness and other issues Firefox users face Mozilla has introduced Reset feature from version 13 onwards, you can find Reset button on “Troubleshooting Information”/about:support page. This feature is also useful to remove malicious toolbars and resets search engine defaults, which is the obvious reason most for using this feature.
After resetting Firefox, you’ll find “old Firefox Data” folder on desktop. Mozilla intention behind on adding this folder to desktop after reset is to let you restore your old profile data if you don’t find much help with reset. And more over you can restore all lost customizations including add-ons without needing install them again using this folder, but how is the question?. We’re explaining that below with step by step in detail.
Restoring Firefox Old Profile Data after Reset
1. After Resetting Firefox, Exit Firefox browser.
2. Backup current Profile folder using tools like Firefox backup tool or MozBackup or you can manually copy Profile folder- click on “Show Folder” on Troubleshooting Information page- paste to another location on hard drive.
4. Open Old Firefox Data folder and copy all files in it with Ctrl +C button, now open Firefox profile folder (use the mentioned above to reach there).
5. Use Ctrl+V to paste them, Windows Explorer shows “confirm folder replace” dialog, at the bottom of it select “Do this for all Current items” (check the screenshot below) and click “Yes” button.
3. Next “Copy File” dialog appears on screen with message “there is already a file with the same name in this location , select “Do this for next (number shown) conflicts“ at the bottom and click on “copy and replace”.
That’s it! your old Firefox profile data has been restored. Open Firefox and check to confirm.