Firefox sync does not recognize my account on a new computer.
I had firefox sync on my laptop and desktop, and it worked fine. On getting a new desktop, I tried to sign in to sync, but I get an "Unknown account" error when ever I do. But I have my laptop next to me, signed in to sync, on that account. Is this some problem with the new version of sync not recognizing old version accounts? It says in order to update to new sync, I have to unlink all my accounts. But I don't want to do that if I can't sign in to recover my sync. I'm not sure what to do here.
"... But I have my laptop next to me, signed in to sync ..."
Which version of Firefox?
Firefox 29 brought a new version of Sync [a year ago], so if you are using an older version of Firefox on that laptop, see this KB article - Sync your Firefox bookmarks, history, passwords and more
You'll need to update Firefox on that Laptop to continue using Sync on it after updating your Sync account.
Thanks for the info edmeister. Unfortunately all versions of firefox involved are 37.0.2 .