Seven Keys to Baldpate (1917).

Poster for Seven Keys to Baldpate (1917)
with George M. Cohan & Hedda Hopper

Based on a 1913 novel by Earl Derr Biggers (the creator of Charlie Chan), this silent film stars theater legend George M. Cohan (who adapted it for the stage) as a writer struggling to finish a novel in an inn where mysterious things are occurring. Actress (later gossip columnist) Hedda Hopper co-stars. (Other versions include a 1935 film with Gene Raymond, Eric Blore, and Walter Brennan.)