Be aware of computer virii and worms that take advantage of e-mail attachments and e-mail clients. Be cautious about receiving attachments even from trusted sources and people you know. It is best not to open any unexpected attachments that are not forewarned by the sender. Do not open ANY attachments directly from your e-mail client. Instead, save them to the hard drive and use Malwarebytes to scan it for viruses. Then open the appropriate application, and open the document from the application's File menu. See Columbia University's security resources for more information.