How to avoid inserting duplicate email field?

[fernborba.sc]

Folks,

I am trying to avoid that one worker insert an already existent email.

How set up SugarCRM in order to check if an email is already recorded in the database before adding a new contact or a new lead.

I am using the last version of Community Edition.

Thanks in advance,
Fernando

[mukulika]

I also want to know this, please suggest...