As was true of many older office buildings, the Guaranty Building was "modernized" during the mid-20th century. Fluorescent lighting, wood paneling and a dropped ceiling were installed in the historic lobby. The exterior storefronts were sheathed in fiberglass. A fire occurred in 1974, and by that time the building was dilapidated and threatened with demolition. Herculean efforts were made to save the building and the support of Senator Daniel Patrick Moynihan was secured for its restoration. This restoration occurred in the early 1980s and was undertaken by architects Cannon Design and Gensler. In 1998, the building was purchased by law firm Hodgson Russ and it became the firm's Buffalo office. The building underwent a further series of restorations in the mid-to-late 2000s managed by Flynn Battaglia Architects.