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Firefox Sync: "Unexpected error" when signing in, "Forgot Password", or Create account.

  • 3 replies
  • 3 have this problem
  • Last reply by philipp

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I noticed that there was a message that said reconnect to Sync. I clicked on it, and typed in my information, however, it keeps giving me an "Unexpected error" message in a red bar above my the e-mail address field. I've tried other tips, and now my bookmarks and add-ons are gone.

I was able to sign into: Please help me as I spent a lot of time and effort on my bookmarks.

Attached screenshots

Modified by hutothebert

All Replies (3)

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hello hutothebert, firefox 29 and above use a new sync login system ( which isn't compatible with the old username/password/sync-key method ( anymore.

however you could try this "hack" to get a new firefox version to connect to an old sync account: enter about:config into the firefox address bar (confirm the info message in case it shows up), right-click somewhere in that page & create a new string preference named services.sync.username with a value like fake.

afterwards you should be able to connect to the old account through the firefox options > sync panel. if this worked and you could import your data successfully, please migrate to the new sync afterwards: Sync your Firefox bookmarks, history, passwords and more

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I'm really grateful, philipp. I was able to retrieve my old bookmarks! Thank you!

However, I still receive the "Unexpected error" message when trying to create a Firefox Sync Account.

Modified by hutothebert

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a user reported that the unexpected error on went away after refreshing firefox here:

Refresh Firefox - reset add-ons and settings