All it takes is one e-mail among a few million under today's rules of e-discovery. Maybe one was an offhand joke about delays or an angry post to the construction manager telling him to buzz off about the crew's safety procedures (before somebody got hurt). Maybe the firm's outdated retention policy has created too many backups, and all that data has to be produced. In a lawsuit, any of these examples could be costly—even a smoking gun.

Firms may have to retain and produce millions of e-mails in addition to an expanding universe of unique file formats, such as BIM, CAD, Primavera, accounting systems and more, depending on the nature of the claim and discovery request.