My Bloody Valentine's acclaimed second studio album, Loveless, had a long, troublesome production. Having gone through 19 producers, 11 major studios, and more than 2 years straight in production time, it had a lot of recorded material from its sessions. Including the album itself, there were two extended plays that used material from these recording sessions that were released: Tremolo and Glider.
Insistent on using every single piece of finished material in order to recoup the funds to record the album, Creation Records planned on releasing two additional EPs. Thinking the material was far too weak for release, the band held onto the master tapes and refused to hand them over. Somehow avoiding a lawsuit for contract violations, the band were just simply dropped from Creation (who were horrified from the dramatic production involved). The EPs were kept a secret until an article from Melody Maker Magazine confirmed them.
Despite the high demand for the tracks, they have never surfaced. The band is still not proud of them. Even when MBV re-issued much of their discography, the tracks were left unissued.
Another thing worth noting is that Loveless itself almost ended up missing completely. The computer that was holding the recorded songs threw them all out of order, with every single piece of the elaborate instrument tracks out of place. Kevin Shields had to piece the whole thing back together by memory, which took weeks. Luckily the album was released as it was intended and on time.