GQ Paul McCartney revealed why he sued the Beatles shortly after leaving the band. He said he had no other option but to sue in order to "save" the music.
McCartney officially announced his departure from the Beatles in April 1970 and, later that year, filed a lawsuit against the group. After years of legal battles, he won the rights to the songs, which had previously belonged to the EMI record label and publisher Allen Klein , who had managed the band after the death of their manager Brian Epstein.
“Because I had to do it, I ended up being the guy who broke up the Beatles and the bastard who sued his colleagues. The only way to save the Beatles and Apple – and release Peter Jackson ’s Get Back , which allowed us to release the Anthology and all those great remasters of all the great Beatles records – was to sue the band.”
He continued: “I said, ‘Well, I’m going to sue Allen Klein,’ and they told me I couldn’t because he wasn’t part of it. ‘You need to sue the Beatles.’” He further explained that if he hadn’t sued the Beatles, they would have lost their rights.
“As you can imagine, it was awful and gave me terrible moments. I drank too much. And it was crazy, but I knew it was the only thing to do, because there was no way I could work so hard all my life and see it all disappear in a puff of smoke. I also knew that if I managed to save it, I would be saving it for them [the other members of the Beatles] as well.”