Hi

Thank you for your question about the Firefox Sync service.

It appears from your question, that you are using Firefox Sync as a back up service. This is not what Sync is designed to do. The Firefox Sync service takes a copy of the data you wish to include and transfers it to a second device (typically a mobile device such as a tablet or a telephone) running a copy of Firefox. The storage in between all attached devices is both temporary and fragile and is not stable enough to be (and is not designed as) a reliable backup service.

If you have a copy of your Firefox profile for desktop Firefox, you may be able to recover your bookmarks and other data. Please have a read of this article.

If you have a copy of your data on a mobile version of Firefox, please follow these instructions to connect it to Firefox Sync to copy your data.

If you change the password of the Sync account or request a new password because you do not remember the password then all data previously stored on the Sync server will be removed and this data is lost and can't be recovered.
This is because this password is used to encrypt the data locally before uploading to the Sync server, so only that original password can decrypt content that is on the Sync server.
This is how Sync works and you should always make sure you do not forget the email address and password for the Firefox account.

If you change the password of the Sync account or request a new password because you do not remember the password then all data previously stored on the Sync server will be removed and this data is lost and can't be recovered.
This is because this password is used to encrypt the data locally before uploading to the Sync server, so only that original password can decrypt content that is on the Sync server.
This is how Sync works and you should always make sure you do not forget the email address and password for the Firefox account.

I have noticed that and it is a big design mistake. There should be a two-way authentication or something similar. I trusted Mozilla with bookmarks that I have collected for years and the platform is locking me out because I forgot my password. This is very bad and I am very sad about that. Mozilla must provide me with my bookmarks because they are d definitely stored somewhere. Please give me a solution about this. I always believed that Firefox was more customer centric than other browsers. This is devastating for a user. Thank you for your answer.

Firefox uses the password of the Sync account to generate a sync key to encrypt your data locally for extra security, so any data that leaves your computer is always encrypted.
You can generate a recovery key that can be used to access sync data when you have lost/forgotten the password of the Sync account, but that still means that you need to store this key safely.

Hi azwris, how did you reinstall Windows? Did you use the built-in Refresh or Reset feature that sometimes moves all your old data to a folder named

C:\Windows.old

Can you find such a folder on your system?

If so:

Before proceeding, please set Windows to show you hidden files and folders: https://support.microsoft.com/en-us/help/14201/windows-show-hidden-files

Then check here:

C:\Windows.old\Users\<user>\AppData\Roaming\Mozilla\Firefox\Profiles\

You might just have one profile folder, or you might have more than one. The bookmark backup files are in a folder named bookmarkbackups in each profile. You can copy promising files to the Desktop to try in a Restore.

Anything so far?

Thank you for your answer. I have deleted the partition and re-installed windows from scratch. Unfortunately the windows.old folder doesn't exist anymore..