When you first setup Firefox Sync in Firefox you would have had to create a new account. Part of that process involves setting a username, password and sync key. If you have not already set up an account, you can then choose a username/password/sync key.

For more details see How do I set up Sync on my computer?. The article refers to a secret phrase, that will be the same as the sync key, it has recently been renamed.

Thanks, a bit confusing but worked after a few tries! Thanks Again!

OK I registered but I don't remember getting a "sync key"? Where can I look for such a thing?

In the Firefox Options/preferences dialog, go to the Sync panel, click on the Manage Account button, and then on the My Sync Key link.

Like the other guys I can not get the sync to work on my mobile (Galaxy S) as I get a Disconnected Incorrect name or password message when I try to connect. Everything is working at the desktop as I have checked the quota used. The problem is at the mobile. I have not downloaded the sync application separately as it seems to be part of the browser. The Account Name used at the mobile is as per the Current Account on the desktop. I have checked the password on the mobile is the same as at the computer end (Tools/Options/Sync/Manage Account/Change password) by trying to change the password to what I thought I had put in as the original password. This told me that I could not change it to the original. The sync key I have input to the mobile is the same as on the Manage Account/Change Password. So what is going wrong here?

Currently (December 3 and 4) the Firefox Sync server is under heavy load and many users are having trouble connecting. For up-to-date status announcements, see https://services.mozilla.com/status/

Is the server still on heavy load ? No way to connect using my email adress or username or typing my synckey or password several times... I use HTC Desire HD with Fennec. What's the matter ?