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

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Firefox Sync works by storing your data on Mozilla servers and syncing it with your computers and devices. When you set up Sync, you enter a username and password in order to prevent others from accessing your account. In addition, we encrypt your data with a Sync KeyRecovery Key in order to keep it safe on the server. This article explains what to do if you forget or loose any of this important information and are unable to access your Sync account.

Note: This applies to the latest Firefox version which can be downloaded from mozilla.org/firefox.

I've lost my Recovery Key

If you don't have a copy of your Recovery Key saved anywhere, or another computer or mobile device that's synced (see Where can I find my Recovery Key?), you can generate a new one.

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 Recovery Key.
  1. In the Menu bar at the top of the screen, click Firefox and then select Preferences or Settings, depending on your macOS version.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 I don't have the device with me.
  6. Enter your account email address and password.
  7. Click I have lost my other device and a new Recovery Key will be made for you.
    Tip: It's a good idea to print or save your Recovery Key so that you can access your information even when you are away from this computer.
  8. Then click Change Recovery Key. You will see the Setup Complete screen.
  9. Click FinishDone to close the setup window.

I've lost my Sync Key

If you don't have a copy of your Sync Key saved anywhere, or another computer or mobile device that's synced (see Where can I find my Sync Key?), you can generate a new one.

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 then select Preferences or Settings, depending on your macOS version.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 I don't have the device with me.
  6. Enter your account email address and password.
  7. Click I have lost my other device and 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.

I’ve forgotten my Sync password — how do I reset it?

To get a new password follow these steps.

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 when you created your Sync account) and fill in the captcha to prove that you're a real person.
  4. Click Email Reset Key. You will receive an email with a link.
  5. Open the email, click the link and a new page will be opened.
  6. Type your new password twice.
  7. Click Change My Password to save it.

Now you're ready to go. Remember to update your password on all your synced devices by clicking Sync Now and Preferences... in the bottom error bar that will be displayed.

I’ve forgotten or no longer have access to my Sync email address

Unfortunately there's no way to change or recover the email address associated with a Sync account. You would need to create a new account following the steps described in How do I set up Sync on my computer?.

I've forgotten my master Firefox password

For security reasons, your master Firefox password is not synced. If you've forgotten your master password and want to stay synced, you'll need to reset your master password and re-add your computer 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 the 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 computer to Firefox Sync.