Enabling Email Verification
Since TeamCity 10.0, TeamCity administrators can enable / disable email verification (off by default).
If email verification is enabled on the TeamCity server, the Email address field in the user account registration form becomes mandatory. When an address is added / modified, the users will be asked to verify their address. If the email address is not verified, TeamCity will display a notification on the General tab of the user account settings.
Verified email addresses will be marked with a green check on the Administration | Users page.To enable email verification in TeamCity:
Navigate to the Administration | Authentication page.
Select the __Enable email verification __option (off by default) .
Save your changes.During the Projects Import TeamCity will take verified emails into account. If there are two users with different usernames, but the same verified email, TeamCity will provide a possibility to merge these users.