hello DCL1, if you have set up firefox sync before and you don't have another working device linked to a sync account after a reinstall you'd need the username, the password & the recovery key generated during the original setup of the sync account to access your synced data. in case you have all those three pieces of information available, you can go to firefox > options > sync > set-up sync > i have an account > i don't have the device with me in order to link the new firefox installation to your existing sync account.

See also:

• https://support.mozilla.org/kb/what-firefox-sync
• https://support.mozilla.org/kb/ive-lost-my-firefox-sync-account-information

Note that your System Details List shows that you have a user.js file in the profile folder to initialize some prefs on each start of Firefox.

The user.js file is only present if you or other software has created it, so normally it wouldn't be there. You may want to check its content with a plain text editor if you didn't create this file yourself.

The user.js file is read each time you start Firefox and initializes preferences to the value specified in this file, so involved preferences can only be changed temporarily for the current session.

• http://kb.mozillazine.org/Preferences_not_saved

This sounds awfully complicated and time-consuming. Why don't you developers allow us to create a Firefox account online to retrieve our different settings whenever we buy a new computer. I just changed mine, have never troubled to sync Firefox with another device since I only use it at home and am in a fix now.

There is a new version of Sync being developed that will work differently.

• http://www.ghacks.net/2014/01/12/mozilla-plans-update-firefoxs-data-synchronization-feature-version-29/