Sorry that you had that problem with Sync. The Firefox Account Password is used to create a pair of encryption "Keys" that encrypts the Sync data when that data is sent to the Sync server and while that data is on the Sync server. Reset the Password and that data becomes useless, as it can't be decrypted with the new Password so that data is automatically cleared from the server to permit the user to continue using that account and load fresh encrypted data. ''IMO, too much security for all but Website Login data; but it works the way it was designed to work - every piece of data has the same encryption level, bookmarks to Logins data.'' ---------------- That said, Sync is intended to be used to synchronize Firefox user data with more than one solitary device, not intended to be used as a "backup medium" for the purpose of reinstalling the operating system on one device. Sync data will be on another device when the Firefox Account Password is '''Reset'''. Log in to the Firefox Account on the device with the data to repopulate the Sync server, then connect to Sync with the device where the operating system has been reinstalled.