Immediately backup the profiles on both machines. Keep the profile backup files and folders somewhere safe outside the Firefox program and profile paths. The Windows Desktop would be a suitable location. * see [[Back up and restore information in Firefox profiles]] * also note the information on bookmarks [[Restore bookmarks from backup or move them to another computer]] Do you use Firefox sync ? *[[Firefox Sync - Take your bookmarks, tabs and personal information with you]] that is not itself a backup, but you may consider the synced second device to be a backup Restored bookmarks overwrite the existing bookmarks. You may still have some left, but unfortunately you could have overwritten most or all of them with corrupt copies. If you backup the profile at least you have access to copies of whatever automatic backups were made. Note in future that it is good practice to periodically make backups. Post back again once you have backed up the profiles, and read the linked articles.

Problems with bookmarks and history not working properly can be caused by a corrupted places.sqlite database file. *http://kb.mozillazine.org/Bookmarks_history_and_toolbar_buttons_not_working_-_Firefox *https://support.mozilla.org/kb/Bookmarks+not+saved#w_fix-the-bookmarks-file