`` The engineering team has been working over the weekend and making steady progress on restoring access to messages for affected users . Yahoo CEO Marissa Mayer admits , ` ` It 's been a very frustrating week '' E - mail has affected 20 % of users , Yahoo says . Mayer has made revamping e - mail a key part of her plan to kick - start Yahoo .
Yahoo CEO Marissa Mayer admits , ` ` It 's been a very frustrating week '' E - mail has affected 20 % of users , Yahoo says . Mayer has made revamping e - mail a key part of her plan to kick - start Yahoo .