Cytomegalovirus (CMV) infections remain a significant problem following various types of transplants that are associated with strong immunosuppressive therapy. Maribavir is a new oral anti-CMV drug with a novel mechanism of action compared to currently available anti-CMV drugs. This study will test the safety and efficacy of maribavir for the prevention of CMV disease when given as prophylaxis for up to 14 weeks following orthotopic liver transplantation.