Schubert: Symphony No.8, 'Unfinished' in B minor. As for the Eighth, with its distinctive, mysterious opening, it is not known why Schubert didn’t complete it: a few jotted-down bars of a third movement is all that we have. The most likely explanation may simply be that Schubert remained unsatisfied with all of his attempts to match the degree of innovation achieved in the first two movements.