Emails are a software tool widely used in the workplace, and by facilitating easy storage and the recording of all information transmitted through them, serve as a means of digital evidence. This chapter analyses their real probative value, for which it is necessary to verify their authenticity and accuracy of content. In addition, the process of obtaining this digital evidence is also important, as, when the employer violates the fundamental rights of the employee in obtaining the evidence, the evidence is illegal and ineffective. Additionally, this illegality is transferred to any possible sanction that the employer imposes on the employee, although legal doctrine and jurisprudence doubt between the qualification of the nullity and the unfairness of a dismissal. The final solution seems to depend on the circumstances of the concrete case, as advocated by the intermediate position, shared here.