Firefox Sync not working? Fix common Firefox sync issues and problems

As Firefox launches its single sign-in feature “Firefox Sync,” many users might consider shifting to it and syncing all their devices. However, nothing was supposed to be perfect and error-free, nor is Firefox Sync. Here is a list of known issues and errors and their solutions.

Firefox Sync not working

I do not see my device in the Devices & apps list

The “Devices and apps” list shows the list of devices which are connected to your Firefox Sync account. It is possible that Firefox sync is working across the mentioned devices, yet it doesn’t show in the list. The 2 possibilities are as follows:

1] Firefox sync was introduced on the later versions of Firefox. If you are used an outdated version of Firefox, it would have to update to the latest version.Common Firefox sync issues and solutions

2] The feature is not yet supported on Firefox on mobile. Thus, if you are using Firefox on iOS, Android or Firefox OS, it would not show the list.

I see duplicates in the Devices & apps list

It happens at times that two sessions on the same device are shown as two different devices. To be on the safer side, click on the Disconnect button to remove the device from the list.

Please note it might be a breach of account security, thus judge accordingly.

My sign in was “blocked for security reasons” on Firefox Accounts

If Firefox sync accounts are breached, it will expose all of your search history and other data to the intruder. To keep users safe, Firefox sync blocks accounts in the event of any suspicious activity. In such a case, the error message “blocked for security reasons” is displayed whenever you try to sync the data and Firefox sends an email with a verification code to the registered email ID.

The account can be unblocked after entering the verification code on the Firefox browser. However, please verify the log-in details of the suspicious login sent to your email due to security reasons.

In case you do not recognize the login attempt, click on the Report this activity link in the email and then change the password for the Firefox sync account.

Remember to check your spam folder in case you have not received the verification email.

I’m having problems confirming my new Firefox Account

1] Confirmation email has not been received: In case you haven’t received the Firefox sync confirmation email, wait for a few minutes, check the spam folder and try resending the message.

2] In case you are using a strong spam filter, add to the white-list.

Disable Firefox Sync on a lost phone or tablet

In case a device is lost or stolen, it could be a serious case of a data breach. Obviously, we can disconnect the device after logging on to the account from, but that device would recognize this instruction only when connected to the internet and synced again. However, till that happens, any data that was previously synced on the device can be accessed by anyone possessing the device.

Disable Firefox Sync on a lost phone or tablet

Firefox Sync’s suggested solution to this issue is to change the password immediately. As per their policy, all data stored is wiped off whenever the password is reset. However, it exists on the primary device (obviously unless the primary device was the lost/stolen one).

Common Firefox Sync errors and their suggested solutions

I set up Firefox Sync, but nothing is syncing

Firefox accounts and sync was available with earlier versions as well but has improved significantly with Firefox updates. Users would have to update all devices intended to be synced to the latest version of the browser.

I’ve lost my Sync account information

As with any account online, a user needs two pieces of information to log in to a Firefox Sync account. The first is the registered email address and the second is the password. In case you have forgotten your email ID, it cannot be retrieved. If you lost your password, go to the Firefox Sync account page and click on “forgot password.” Follow the instructions to reset it.

My bookmarks aren’t syncing to Firefox for Android

Android has its own limited capabilities. It cannot store more than 5000 bookmarks, whether or not using Firefox Sync, but in case you are syncing, it won’t store the surplus bookmarks even if they are present on the primary device.

Firefox Sync shows a “Cookies are still disabled” error message

Firefox Sync accounts require the user to enable cookies on every connected device. We can do it for all the devices at once.

Firefox Sync not working

1] Go to This is a protected site since the website address is preceded by “https://.”

2] Behind the URL on the address bar, we could see a green colored padlock symbol.

3] Click on the forward pointing arrow to open the site security page and then click on “More Information.”

4] Go to the “Permissions” tab.

5] Change the Set Cookies option to Allow. You might have to uncheck the Default checkbox.

Hope this troubleshooting guide helps you fix your problem.

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Karan Khanna is a passionate Windows 10 user who loves troubleshooting Windows problems in specific and writing about Microsoft technologies in general.