I encountered peculiar behaviour in Firefox (Macbook Pro / High Sierra). The Firefox Awesome bar (address/search bar) stopped showing suggestions. It did show some suggestions but only after typing 'http://'. After weeks of torment I discovered that the problem wasn't limited to the awesome bar itself – the history and bookmarks stopped working properly as well. History ceased displaying recently visited sites (only the ones I visited weeks ago) while I also could not add or delete bookmarks ('Bookmark this page' and 'Delete bookmark' functions didn't do a thing). I tried many fixes, starting off by googling for solutions. I tried clearing cache, disabling search suggestions and enabling them again under Preferences, reinstalling Firefox, resetting PRAM, updating my OS. None of the above fixes worked. I fixed all the problems by following this guide on repairing faulty bookmarks: https://support.mozilla.org/en-US/kb/cant-add-change-or-save-bookmarks Removing the xulstore.json and places.sqlite files and restarting Firefox did the job, everything is working smoothly again. I'm sharing this in case there are others like me, who are searching for a fix to the awesome bar only and not to the bookmarks or history.