Hi le.joncour.antoine, I'm sorry to hear about this problem. When you say your Firefox reinstalled itself, do you recall exactly what happened? Was it one of the routine updates? If you haven't already, could you close out of Firefox and do a normal MacOS shutdown and restart to complete any pending updates and release any file locks. If Firefox again starts up without your bookmarks, here are two things to check: '''''Bookmark Restore Feature''''' Check the "Restore" menu in the "Library" window to see whether it shows any older backups you can restore. This article has more info on where to look for that: [[Restore bookmarks from backup or move them to another computer]]. Did that menu have any older backups? '''''Profile Manager Page''''' Inside Firefox, type or paste '''about:profiles''' in the address bar and press Enter/Return to load it. This page should list at least one profile and could list many. (Each profile has two folders and one or more buttons. Do not use any Remove buttons!) The profile that Firefox is currently using will have this: '''This is the profile in use and it cannot be deleted.''' Do you have another profile named '''default''' or '''default-release''' or default-''longnumber'' listed on this page? If so, you can check whether it is the one you were using recently by clicking its '''Launch profile in new browser''' button. If it isn't what you want, simply close that new window. If it IS what you want, back on the about:profiles page, click the '''Set as default profile''' button for that profile so Firefox uses it automatically at the next startup. Did any other profile have more of your data?