My Firefox had a Gmail session active, then I was needed to make a fresh install of Opera browser. After the installation of Opera finished, I pretended to log in into my Gmail, I was expecting it was necessary to me to set my username and password and then my phone verification, but no, my session automatically opened.

From previos experiences, when I pretended to start session into Gmail from Chrome (or any new browser) it required me phone verification and username with password.

To me that is not a problem, but why did it happen?

  • 1
    Can you be more precise about exactly what happened when you "pretended" to log in? Did the browser auto fill the username and password? Do you have two step authentication enabled? Commented Aug 20, 2015 at 12:24
  • Well, when I entered the url gmail.com, the browser redirected to my inbox. It never showed the login panel. Yes, I have two steps authentication enabled. Commented Aug 21, 2015 at 21:38
  • It seems to be a problem with cookies, because after all, I logged out from Gmail in Opera. Then when I tried to access again, this time I saw the loggin form, but I couldn't log in, Opera showed me this page: accounts.google.com/CookieMismatch, I had to clean caches from recently installed Opera and then it acted normally. Commented Aug 21, 2015 at 21:41
  • Exactly the same problem here
    – Gabber
    Commented May 4, 2016 at 14:58

1 Answer 1


I'm speculating here, but a couple of possibilities come to mind:

  • you already had an active session with your Google account and signed in from the same IP address; it seems logical to assume it was you

  • Did you copy your Firefox configuration to Opera? Did that include cookies? User agent? Google may have believed that you were using the same browser, especially since it was using the same IP address for your active session

  • perhaps neither of these things are absolutely true, but instead Google only offers the extra security if it doesn't have a high degree of certainty who you are. I'm sure Google has a number of things they look at to make that determination

  • In fact, I access the same account from a few personal computers. I didn't notice if I copied Firefox configuration. What I know, is that after logging out and after trying to log in again, Opera showed me this page: accounts.google.com/CookieMismatch Commented Aug 21, 2015 at 21:44

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