Firefox now comes with a new, Accounts-based version of Sync - no device codes required. If you use the old Sync, a tutorial that will automatically guide you through the transition to new Sync.

If you've lost access to old Sync before getting the chance to upgrade, but still have your device code, you can recover your information and upload it to the new Sync:

Turn on old Sync

1. Use the Profile Manager to create a new profile.
2. Launch Firefox with your new profile.
3. Type about:config into the address bar. (If the This will void your warranty! message shows up, click I'll be careful, I promise! button to continue.)
4. Create a new preference by right-clickingcontrol-clicking anywhere on the list to bring up the menu.
5. Choose New from the menu, followed by String.
6. In the New string value box, type services.sync.username as the preference name.
7. At the next prompt, enter any as the value.
8. Close the about:config page.

Follow the next section to sign in to old Sync and recover your data.

Sign in to old Sync and download your data

1. Click on the menu button The image "new fx menu" does not exist..
2. Click on OptionsPreferences.
3. Click on the Sync panel, followed by Set Up Firefox Sync.
4. Follow the prompts to sign in to your old Sync account.

After you've synchronized all your old Sync information, see Sync your Firefox bookmarks, history, passwords and more to transfer your data to new Sync.