Sorry to hear about this problem. I am not aware of any way to recover a backup of your older Sync data. However, at least for bookmarks, you should have a backup in your Windows installation of Firefox that you can recover using the Restore menu. More info in this article: Restore bookmarks from backup or move them to another computer. Does that work?

Sinc does not store old data.

Shut down the old sync. Then create a new account. or Resetting the sync password, or changing its e-mail, will remove all data from the servers.

The data in your profiles will not be affected.

By law, victims of hacking are entitled to have their data recovered.

By law, victims of hacking are entitled to have their data recovered.

Really? I haven't heard of that. You can try the form linked on the following page for a "Data Subject Access Request" and see whether Mozilla has the data:

https://www.mozilla.org/privacy/#contact

Are you sure you are still connected to the same Firefox account? You didn't reset the password of the Sync account because you forgot this password?

• https://support.mozilla.org/en-US/kb/ive-lost-my-firefox-sync-account-information

A few days ago, I used the form, but have yet to hear back.

There are several posts above.

There are several posts above.

I mean I have not received a response directly from my data request that I sent a few days ago.

Hi

Please appreciate that is the weekend, Mozilla staff may not be available and that a DSAR has a month (in the EU) to be completed.

Firefox Sync is not designed to be online storage, it is designed to help Sync data between copies of Firefox. I too (in a background that has involved working with GDPR and data legislation) am unaware of the legislation that you mention.

What makes you believe that your data was hacked?

I noticed all my saved passwords had suddenly disappeared without my knowledge, making me believe I was hacked.

If you type about:logins into the address bar, are any user credentials shown?

(Please do not share exact details, this is an open forum.)

Firefox 80+ has a logins-backup.json file in the profile folder that can be used in case of issues with logins.json or to undo an accidental delete/update of a password. You can check if you can find this logins-backup.json file in the profile folder or in a backup.

• https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data

If you type about:logins into the address bar, are any user credentials shown? (Please do not share exact details, this is an open forum.)

There are no credentials shown (there used to be ten).

You can install the About Sync extension in Firefox 72 and newer on desktop to check what data is stored on the Sync server via the about:sync page provided by this extension.

• About Sync https://addons.mozilla.org/firefox/addon/about-sync/

Close and restart Firefox to access the about:sync page added by this extension (see the about:about page for possible about pages).

You can install the About Sync extension in Firefox 72 and newer on desktop to check what data is stored on the Sync server via the about:sync page provided by this extension.

• About Sync https://addons.mozilla.org/firefox/addon/about-sync/

Close and restart Firefox to access the about:sync page added by this extension (see the about:about page for possible about pages).

Not able to recover my synced passwords from there.