In this scenario, Login and Registration form both have same fields: Email and Password. However both forms are on different pages. By default, Registration form is displayed when user lands up on the home page.

What would be optimal user experience for already registered user, when user tries to login using registration form with valid email and password

  1. Should error message "The email is already registered" be displayed
  2. User should be logged in and taken to the registered account
  3. any other suggestion
  • Stepping back a little - what are the triggers for Logging in and Registration? Surely these are not the same trigger?
    – SteveD
    Apr 29, 2016 at 11:08
  • The triggers might or might not be same. But the question is what would user expect in this scenario. As a layman, what would user expect if he/she is already a registered user. Apr 29, 2016 at 11:16

3 Answers 3


Short answer

The optimal user experience would be to log them into their account.

Long answer

However, one could put an argument forth that if the user realises they just tried logging in via the wrong screen, they would instead expect to be presented with an error message as per your first point. The reason for this is that most sites use this approach and, because of this, there is a familiarity with this approach.

Why does familiarity matter? Because familiarity breeds expectation, and this usually leads to a better user experience because it matches what users are expecting. Here is some further reading to back this assertion up:

I would argue that you don't want to step away from a familiar approach unless you have something that is significantly better and therefore warrants the change.

So, would logging the user in regardless of the screen they were on warrant such a change? I believe it does because the change from the norm is not too drastic and it most certainly improves the user experience.

Finally, as an aside, you may also find the following article interesting: https://articles.uie.com/user_expectations/

  • I 100% agree. Great response by the way! Jul 16, 2018 at 9:31

From a user experience perspective, I would say that you need to fix the triggers first before you solve any other problem, because you might be trying to solve the wrong problem.

Clear triggers mean users have clear expectations about what will happen.

So I guess you have some options:

  • Have a separate Login link and Register link

  • Have a simple Login link and the Login page shows a "Don't have a account? Register here" link.

It is ok for the login page and the Registration page to share common fields, but I would say that the Registration page will show additional information explaining the benefits of registering.


Well, in my point of view, if the user visits the homepage, he should be shown the Login window with a signup CTS just below or on the side. Obviously if the user hasn't signed up for your website, he won't try logging in at the first place and will instead click on the Signup button. The best example is facebook, the site with maximum number of users.

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