Hi memomohannad.

Have you used the same username and password as before the format, or did you reset the password before setting in the new installation?

Michal Stanke said

Hi memomohannad. Have you used the same username and password as before the format, or did you reset the password before setting in the new installation?

yes the same user and pass :) all my work lost , i wonderd if there is any old databass in mozilla server , so ican recover by their suggestion

Note that Sync isn't designed to be used as a backup device, but merely to sync data between multiple devices. It is not guaranteed that you can restore data from the Sync server in case of problems with your OS or because you otherwise lost data. Requesting a new password because you forgot it or changing the password for the Firefox Sync account will wipe all data stored on the Sync server and you won't be able to retrieve data that was stored previously. Best is always to backup your personal data locally to be sure to be able to recover from issues.

• https://support.mozilla.org/kb/Backing+up+your+information
• http://kb.mozillazine.org/Profile_backup

Depending on how you formatted, Windows may have preserved some data. Can you find this folder:

C:\Windows.old\

If so, within that folder, can you see this:

C:\Windows.old\Users\username\AppData\Roaming\Mozilla\Firefox\Profiles

If you can't get to AppData, turn on viewing of hidden files. This Microsoft article might still work in Windows 10:

http://windows.microsoft.com/en-us/windows/show-hidden-files

If you have one or more semi-randomly named folders there, that would be promising for data recovery.