Schubert finished only the first two movements of his B-Minor Symphony (D. 759), and they remained unseen and unheard for the last six years of his life, indeed until 1865. The best available evidence indicates that he sent his only score to the Music Society in Graz sometime after September 1823, and that from that point on, at the latest, he had given up any plans to complete the two remaining movements. But why?
At least part of the answer is to be found in several consistent patterns Schubert followed in the conduct of his career. He did not return to unfinished works after he had laid them aside for a period of several months; the only exception to this pattern is the Mass in Ab. And not until early 1824 did Schubert begin to seek publication or public performance for newly composed works in the large multi-movement instrumental genres--in Beethoven's genres. Finally, in October 1822, the date on the score of the B-Minor Symphony, Schubert could have had no reasonable expectation of a full performance of a four-movement symphony, in Vienna or anywhere else, by an orchestra of adequate quality. His subsequent hopes and exertions for a performance of a symphony, for his "Great" C-Major Symphony, proved illusory and unavailing, even after he had become much better established.