If you used a remove personal settings option from Windows or Firefox,you may well have permanently lost those bookmarks. * Undelete<br>If you did that then timely use of a file undelete utility and a good helping of luck are likely to be required to attempt recovery (probably best to stop using the computer entirely, until you have such utility). *Your Own Backups<br>You could have a backup system in place that backs up such files or the firefox profile, and you may be able to use that. * Synced to another machine<br> you may have the bookmarks synced on another machine, or even on an external server **see [[what is firefox sync?]] See also [[lost bookmarks]] but I am not sure any of that applies in this case, it is worth reading it though Normally