Sometimes things go missing. Every once in a while they show up again.
Richard Burton starred in a very successful Broadway production of Shakepeare's Hamlet. By all accounts, the production was profitable and garnered several Tony nominations. But apparently the movie version left something to be desired. It was recorded and edited from several live performances, and played in movie theaters for only two days, bringing in only 4 million dollars. All copies of the film were to be destroyed by contractual agreement, however one survived. After Burton's death, one copy of the film was found in his belongings, and it has since been released on VHS.