Hi zoomy,

First check that you still have data in your sync account.

Firefox button > Options > Sync > Manage Account

It should tell you how much data is stored in the account. Is there any?

If there is still data in the sync account then you can follow the instructions in this article How do I set up Sync on my computer?. Refer to the 'How much of my data is synced?' section. Change the option to 'Replace all data on this computer with my Sync data'.

I hope that works for you.

If there is no data in your sync account you will be able to get it back by syncing from another computer. Just make sure that the settings on that computer are not replaced by the blank account again. You can use the 'Replace all other devices with this computer's data' option to prevent this.

Please note that Firefox Sync is designed only to sync details between devices not as an online backup tool. If you are formatting a partition it is generally best to backup your profile folder along with any other data. See Profile Manager - Create, remove or switch Firefox profiles for more detail.

--Edward

I have got data there, but everytime I try to do something, everything that has been syncronised today loads :-/. Is my older data permanently lost ;-/?

Right so it is loading only the data which has been uploaded since your first sync today?

What other devices are you syncing to? As I suggested above you will need to use the data still on those devices to sync back up to the account and then down to the computer.

Yes, only today's data. I have always been using Firefox Sync always to store settings from only one Windows Fx browser at a time and I have never used my account to synchronise other devices.

I am afraid that I think the data is lost then, unless you have a backup of your profile folder somewhere. Or unless it can be recovered using a file recovery tool such as Recuva: http://www.piriform.com/recuva

Firefox Sync is not really designed as an online backup tool, it is just for syncing data between different devices.

I'll ask another volunteer to check this statement to make sure I am right.

I've added a Sync tag to this thread, so maybe one of the devs that deal with Sync issues will notice this.

If you have replaced the data on the sync server then I agree with eddyc that your data is most likely lost.
Sync isn't designed to be used that way, so unless you configure Sync properly before syncing the first time then you will replace your data on the sync server.

It is always best to back up your data locally if you want to be able to restore it after you've formatted your hard drive and reinstalled the OS.

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