Firefox Sync troubleshooting and tips

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  • Creator: Ibai
  • Comment: The way a new Sync Key is generated has been modified.
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If you've run into a problem with Firefox Sync, this article will walk you though the most common solutions.

Error While Syncing

There are number of things that can cause this:

  • Your Sync client isn't compatible with the data you have on the Sync server. See I upgraded something and now Sync doesn't work (below)
  • Your password is incorrect. See How do I change my password? (below)
  • Your Sync Key is incorrect. See Sync your Firefox bookmarks, history, passwords and more
  • You've set a master password and haven't entered it.
  • The Sync servers are under a heavy load - in this case, the error will stop when the server load returns to normal.

I upgraded something and now Sync doesn't work

We recently changed a lot of things about how Sync works. One of those was the way it stores your information. If you've updated one of your devices to Firefox 4 Beta 8, Firefox 4 B3 for mobile, or the Sync extension to version 1.6, your Sync data has been updated to the new format. This means that any of your other devices which have not been updated, will need to be updated in order to keep syncing.

Note: After updating, you may need to connect your device again. See How do I add a device to Firefox Sync?

Where can I find the code to add a device to Firefox Sync?

Where can I find the code to add a device to Firefox Sync? shows you how to find the code on a mobile device, an iPhone and another computer.

What is a Sync Key and where can I find it?

See Sync your Firefox bookmarks, history, passwords and more

I've lost my Sync Key, what can I do?

If you don't have a copy of your Sync Key saved anywhere 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 and have to be re-added to your Sync account.
  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 tab.
  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 on "I've lost my other device"
  8. A new Sync Key will be made for you. Please take a moment to print it out or save it on your computer. Then click Change Sync Key
    Lost Key 2
  9. You will see the Setup Complete screen. Click FinishDone to close the setup window and take you back to the Sync panel.

How do I change my password?

  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.

Check to see if other extensions are interfering with Firefox Sync

  1. Follow these instructions to disable all extensions except for Firefox Sync.
  2. Then test for faulty extensions.

This didn't solve my problem - I still need help!

If you're still having problems with Firefox Sync, please try asking your question in our support forum.