To restore the Bookmarks of your Firefox after you have downgraded or upgraded it, please do the following:
-
Click the menu button (
) in the far top right corner.
-
Click the question mark icon (
) at the bottom to the right of the Customize option.
-
Select Troubleshooting Information.
-
Select Open Folder in the Application Basics list.
-
Once the file is open, close your Firefox.
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Scroll down to find the "places.sqlite" file and right-click to delete it.
-
Finally, open your Firefox and your Bookmarks should be restored.