From Alan Bennett’s 1996 diaries, on his early musical upbringing:

“I also bought a record of Schubert’s Unfinished Symphony, doubly unfinished in this case as I only got one record out of a set of three, so it wasn’t until years later that I found out how it officially didn’t finish.”

Generally I don’t rate drôle ads much, but this is apposite:

Cf. Creative tribulations, and for another unfinished work, Modulation: Schubert and Coltrane.