After Prince's deal in April 2016, attention focused on the trove of unreleased material that he kept hidden in two storage vaults at Paisley Park, his studio complex outside Minneapolis. A conflict in Prince’s estate over a $31 million deal with Universal for music rights means that much of the vault may not see daylight for months or even years to come. And music industry lawyers say that copyright entanglements may complicate or even prohibit the release of more music.