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I can't add a second device (Firefox Desktop, Mac) to the Sync service.

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  • Last reply by philipp

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The error is "Unknown account: Sign up". I can log in just fine with the same account on https://account.services.mozilla.com/ though.

Particular to my setup:

* My email address contains a "+". 
* I didn't remember my password, so I changed it to a new one in the Preferences on my first device (but, as I said, the new one works fine on https://account.services.mozilla.com/)

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hello, firefox 29 and upwards is using a different sync system which isn't compatible with accounts set-up in older versions. you'd have to create a new account to migrate to the new system (you can use the same mail there): Sync your Firefox bookmarks, history, passwords and more