I have the same problem on an old laptop running on Windows Vista Ultimate 64-bit. Every time I sign in to Synchronization, I get signed out automatically and the same error message pops out. I try singing in again and the same result repeats over and over again. I have uninstalled and reinstalled Opera several times and it did not help. I have written Opera but I have not received any reply. I have filed a bug report using Opera's Report Bug Wizard, but I have not received any response.
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