[Kubrick] insisted that the only Also Sprach recording he would use was the Karajan/VPO version.
John Culshaw covers this odd transaction in his autobiography,
Putting the Record Straight. When Kubrick approached Decca about using the Karajan/VPO recording of
Zarathustra, Decca agreed but stipulated that "no credit should be given to either Decca or Karajan in the film itself, which meant that other companies were able to reap the benefit by rushing out recordings of
Zarathustra as soon as the film became a success. Karajan was understandably furious and threatened to sue both Decca and MGM, but Decca managed to soothe him by one means or another." Apparently, Decca didn't want their recording of
Zarathustra "cheapened" by association with a science fiction movie. Remarkably, when MGM released the official soundtrack recording of
2001, they used Karl Böhm's Berlin Philharmonic recording of
Zarathustra rather than the one actually in the film.
Kubrick treated Alex North rather badly throughout the whole process. He pressed him very hard and set unreasonable deadlines for the production of the score in the first place—to the point that North suffered a physical collapse—and then didn't have the courage to tell him he wasn't going to use his score until the film was about to be released.
There are two recordings of the North score floating around: the one by Goldsmith Wade mentioned, and an earlier one conducted by composer Henry Brant, the man who orchestrated it all for North in the first place.
James