Sorry, your also need the Sync Key / Recovery Key that was created when you set up Sync and was being used before the reformat. That Key is what is used to encrypt / decrypt your data as it is uploaded / downloaded between your devices and the Sync server. Without that exact key your data is worthless, it is the encryption algorithm for decoding your data.

Any chance you are using a 2nd device on that Sync account, or were you trying to use Sync to just backup and restore your data on that one device?
If so, Sync isn't intended for that purpose.

With a 2nd device you could recover the correct Sync Key for your account.

Another thing, you probably wiped your data from the Sync server by using that "lost other device button" and then you received a new Sync Key

Hi the-edmeister, what if the second device was an iphone with a still running firefox Home app? Would I be able to retrieve the synch phrase somehow? Thanks very much for your support, Alessandro

Hi Alessandro,

Unfortunately Firefox Home is only a client and it doesn't store the Recovery Key so you are out of luck.

I have this problem too.

What really sucks is that Firefox never TOLD ME that I needed the recovery key, now its long gone same as my data, which was, by the way, very important.

This is a very serious bug IMHO, Firefox should emphasize the importance of your recovery key, and that your password is NOT the encryption key.

I agree with jbaldwin9182. This is a serious bug. The way sync is presented, one might easily interpret it as being a way to backup your data. I also used sync as such, having read the description and being assured by two others that really, all I needed to do was make an account and that would be that. Without this sync key I never learned about important data, over half of which irreplacable, disappeared just like that. Why wasn't I given notice that I needed a sync key? I would have saved it five times over.

There are hardly any services which people who know little of computers (like myself) are used to which ask for more than your username/email and password. People are not likely to realise you need anything else unless you tell them. It is easy to tell the user that this was not intended as a backup device, but the description does lead to the conclusion that it is, in fact, a way to backup your data. Please don't tell people they are doing something wrong when they are not being properly informed of what they should be doing in the first place.