You can check this article. *https://support.mozilla.org/en-US/kb/recover-user-data-missing-after-firefox-update

where are my bookmarks

''<p>chiampia@bellsouth.net [[#answer-1622398|said]]</p>'' <blockquote>where are my bookmarks </blockquote> Do you recall the events that occurred between the last time Firefox was working normally and the first time you noticed your data missing? For example: * System crashed * Firefox suggested a Refresh or Reset * Firefox installed updates * Nothing unusual In the article cor-el mentioned, the first section has steps to check whether Firefox created a fresh profile (new data folder). It has the steps to return to your previous profile -- or check whether Firefox reports an error in trying to do so. See: [[Recover lost or missing Bookmarks]].