Hi Steph, sorry you ran into this issue. A couple quick questions that might help us understand what happened: * When Firefox reopened, did it look completely like a fresh install (no bookmarks, no history, signed out of everything)? * Did you see any message about your profile or being asked to create a new one? * Have there been any recent changes to your computer or Firefox, like reinstalling it or restoring from a backup? This usually happens when Firefox opens a new or different profile after an update, so your data is still on the device but not being loaded. This article walks through how to check for that and recover it: https://support.mozilla.org/en-US/kb/recover-user-data-missing-after-firefox-update