Firefox Sync allows you to sync your bookmarks, logins and passwords, browsing history, tab settings and other items across various devices. See How do I set up Sync on my computer? to learn more about how to turn on Sync.

You can disable Sync, if you like, to avoid syncing your data across certain devices when creating or signing into a Firefox Account. You'll remain signed in to your account even after Sync has been disabled, unless you decide to sign out. You can also disable Sync for devices that have been synced previously. For additional information, see Remove a synced device from Firefox Accounts.

Disable Sync for previously synced devices

To disable Sync for previously synced devices:

1. In the Menu bar at the top of the screen, click Firefox and select Preferences.Click the menu button and select Settings.
2. Click Sync from the menu options to open the sync settings panel.
3. Click the Change… button in the Syncing: ON subsection.

   The Choose What To Sync pop-up will open.

   

4. Click Disconnect…. A confirmation prompt will appear.

   

5. Click the Disconnect button in the prompt.

This Firefox profile will stop syncing your account but won’t delete any data or settings. The Sync panel of your Firefox Settings page will now show Syncing: OFF.

Disable Sync for an existing Firefox Account on a new device

You can disable Sync when first signing into an existing Firefox Account on a new device. (This also applies when you first create a new Firefox profile.)

1. Enter your email address on the Welcome to Firefox page that displays when you first start Firefox and click Continue.

   

2. Enter your Firefox Account password on the next Sign In screen.
3. Click Don’t sync this device.

   

You will be signed in to your Firefox Account but Sync will not be set up for the new device.