Starting with FF29, a new version of Sync has been introduced which uses Firefox accounts. https://support.mozilla.org/en-US/kb/how-do-i-set-up-firefox-sync

Seamonkey hasn't adopted the new Sync yet. So you cannot set up a new Sync account or pair a device anymore (bug 998807). Workaround: Use an older version of SeaMonkey for such tasks for now.

I have already updated to the new Mozilla sync, now my SeaMonkey will not sync to my existing account, any way to get it to do so?

I guess you'll have to wait until Seamonkey implements the new sync.

You could also go back to the old sync on all devices, but that would be a big hassle and not recommended.

I will just have to be disappointed for a bit... Thanks for your help Christ1.

You would have to install a Firefox 28 version and connect to the old Sync account. Then you can update again to Firefox 30.

• http://download.cdn.mozilla.net/pub/mozilla.org/firefox/releases/28.0/

bug 1022319 is for SeaMonkey to support the new Sync. If you're trying to sync SeaMonkey with Firefox for Android or the latest Firefox, you are out of luck.

I requested that the support article on updating to Firefox sync mention that SeaMonkey doesn't work, and filed bug 1078092 that http://www.seamonkey-project.org/doc/sync should mention this bug.