I've lost my Firefox Sync account information - What to do

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Using Firefox Sync requires remembering important information, that is the username, password and Sync Key. In addition, for some devices with a set master password, you also need to remember it. This article explains what to do in case you've lost some of them.

I’ve lost my password

In order to get a new password follow the step above.

Warning: Your other devices will stop syncing unless you update them with the new password.
  1. Go to https://account.services.mozilla.com.
  2. Click Forget your password?.
  3. Enter your username (this is the email address you used to sign in) and the two words of the image.
  4. Click Email Reset Key. You will receive and email with a link.
  5. From an email program, open the email and click on the link. A new page will be open.
  6. Type twice your new password.
  7. Click Change My Password to apply the change.

You are ready to go. Remember to update your passwords in all your synced devices by clicking Sync Now and Preferences... in the bottom error bar that will display.


I’ve lost my username

Unfortunately at this stage, there's no way of recovering your username, which is an email address, even if you have your Sync Key. You would need to create a new account following the steps described in How do I set up Sync on my computer?.


I've lost my Sync Key

If you don't have a copy of your Sync Key saved anywhere or a computer that is already synced (in this case, see Viewing your Sync Key) and want to use Sync without creating a new account, you can generate a new Sync Key.

Warning: This will erase all of your data stored on the server. New data will be secured by this key and then uploaded. Your other devices will stop syncing unless you update them with the new Sync Key.
  1. In the Menu bar at the top of the screen, click Firefox and select Settings (select Preferences on older macOS versions).Click the menu button Fx89menuButton and select Settings.
  2. Click on the Sync panel.
  3. Click Set up Firefox Sync and a new window will open.
  4. Under I already have a Firefox Sync account, click Connect.
  5. Click on I don't have the device with me.
  6. Enter your account email address and password.
  7. Click on I have lost my other device. A new Sync Key will be made for you.
    Tip: It's a good idea to print or save your Sync Key so that you can access your information even when you are away from this computer.
  8. Then click Change Sync Key. You will see the Setup Complete screen.
  9. Click FinishDone to close the setup window and take you back to the Sync panel.


I've lost my master password on a device

For security reasons, the master password is not synced even if passwords and preferences are synced. If you've set a master password on a device, you need to enter it so that you can access to your usernames and passwords. For more information on the master password, see Use a Primary Password to protect stored logins and passwords.

If you've lost your master password on a device and want to stay synced, you need to reset your master password and re-add your device to Firefox Sync.

Warning: This will clear your usernames and passwords stored on your device and disconnect you from Firefox Sync. However your usernames and passwords on the Sync server won't be cleared.
  1. Reset your master password by following instructions in Reset your Primary Password if you've forgotten it.
  2. Click the Firefox menu Fx89menuButton and select Exit.Click the Firefox menu at the top of the screen and select Quit Firefox.Click the Firefox menu Fx89menuButton and select Quit.
  3. Start Firefox
  4. Re-add your device to Firefox Sync.