Disable Firefox Sync on a lost phone or tablet

Revision Information
  • Revision id: 38001
  • Created:
  • Creator: Tonnes
  • Comment: log into -> log in to
  • Reviewed: Yes
  • Reviewed:
  • Reviewed by: iNerd
  • Is approved? Yes
  • Is current revision? No
  • Ready for localization: No
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Revision Content

So you've just lost your device (sorry about that) and you realize you've been using Firefox Sync to get all of your usernames and passwords on it. This article describes what you should do to prevent someone from accessing your passwords.

First, change your sync password from a synced computer

This first step will prevent your lost phone from connecting to the sync server and getting all of the new passwords that you will have to create.

  1. Click the menu button Fx89menuButton to open the menu panel.
  2. Click your Mozilla account (your email address or sign in).
  3. Click Manage Account (or visit https://accounts.firefox.com).
  4. On the Mozilla account page, scroll down to the Security section and click the Change button next to Password.
  5. Follow the steps to enter your old and new passwords, then click Save to finish.

Second, change all of your account passwords from a synced computer

If you were protecting your device with a master password and are sure that Firefox is closed, that's all.

In other cases, do the following.

It's important that you change your sync password before changing your other account passwords so that your phone doesn't get a copy of your new passwords.

This part is more time consuming but vital. If you don't change the passwords for things like your bank account, it would still be possible for someone with your device to log in to your account.

See Create secure passwords to keep your identity safe for an easy way to create better passwords.