Bono has described U2's latest free album as a "bottle of milk in people's fridge that they weren't asking for.
The frontman, 54, came under fire when Songs of Innocence was automatically downloaded into iTunes users' music collections in September, whether they wanted it or not.
Apple received so many complaints that a tool was released to allow music fans to remove the album.
Now, even Bono has admitted that it was a PR disaster and insisted the band were unaware of the promotional stunt details.
"It is a gross invasion! But it was kind of an accident." he told Rolling Stone. "The milk was supposed to be in the cloud. It was supposed to be on the front doorstep."
The "One" singer's comments see him backtrack on his previous description of the unconventional release as a "drop of megalomania, a touch of generosity and a dash of self-promotion".
"I had this beautiful idea and we got carried away with ourselves," he said in a Facebook Q&A session earlier this month. "Artists are prone to that kind of thing."
U2's history with Apple has been turbulent, with Bono admitting to throwing a "tantrum, like a child" and telling late founder Steve Jobs to "go fuck [himself]" after a disagreement.
The Irish rock group teamed up with Apple rival Blackberry for their 360 Tour instead, before resolving the dispute with Apple before Jobs' death in 2011.
Controversy aside, Songs of Innocence enjoyed chart success last weekend when it charted at number six on the Official UK Albums chart.
"We're heading for Top 10 all over the world in our sixth week after release (for free in September) which is a great result, added to the over 26 million people who have already downloaded the album," said Guy Oseary, U2 manager.
It was reported that five per cent of iTunes users (26 million), downloaded Songs of Innocence when Apple placed it on their devices on 9 September.
iTunes might have 500 million subscribers, but U2's figure still ranks their album at joint 32nd place on the Top 40 best-selling albums of all-time list, alongside Britney Spears' 1999 hit ...Baby One More Time.
"To help put this in perspective, prior to this, 14 million customers had purchased U2 music since the iTunes store opened in 2003," said Eddy Cue, Apple vice-president.
Micheal Jackson's Thriller sits at number one on the best-selling list, having shifted around 60 million copies since its 1982 release.Reuse content