Alban Berg
Soon after he had finished the Violin Concerto, Berg was stung by an insect. This formed an abscess and he was rushed to hospital but he died. The concerto had not yet been performed. He had not finished Lulu. The third act was only sketched in short score (showing the main notes, but not exactly what each instrument plays). When the opera was first performed, Act III was just acted out in mime while some other music by Berg was played. Berg’s widow Helene did not want anyone else to finish the opera, so Act III was never performed until after Helene died in 1976. It was finished by Friedrich Cerha and performed in 1977, although a court action had tried to stop it from being performed.