With millions of loyal readers and a fantastical setting, Stephen King’s “The Dark Tower” book series has long tantalized Hollywood. The movie business is always on the prowl for the next “Lord of the Rings” or “Harry Potter.” King’s novels, about a mysterious gunslinger on a quest to save the universe, had the markings of a potential blockbuster.

However, getting the promising adaptation to the big screen took more than a decade and suffered several setbacks along the way, as one top director and screenwriter after another — including J.J. Abrams, who originally optioned the material — tried and failed to wrest the author’s eight-book opus into a workable film. After Universal Pictures scrapped plans to make a series of interconnected films and television shows with Ron Howard running point, Modi Wiczyk, co-founder of Media Rights Capital, set the project up under a co-financing deal with Sony Pictures.

In 2015, MRC and Sony jointly announced they had found a way into the story and tapped Nikolaj Arcel, the Oscar-nominated Danish filmmaker behind “A Royal Affair,” to direct the movie.

With “The Dark Tower” poised to debut this weekend, multiple sources told Variety that the creative process — particularly in post-production — was plagued with problems and clashing visions. Wiczyk and Sony Pictures chief Tom Rothman downplay any suggestion that the movie faced major hurdles.

But when Arcel delivered an early cut of the picture that alarmed Wiczyk and Rothman, they considered bringing in a more experienced filmmaker to recut it. While the two men deny this and insist their joint contribution was limited to giving the director notes, one insider said that Rothman spent hours in the editing bay offering his input.

Arcel seemed the ideal director on paper — “A Royal Affair” had earned an Oscar nomination and proved he could handle lavish spectacle, while his screenwriting work on “The Girl With the Dragon Tattoo” demonstrated he could adapt beloved novels. Also, he was a big fan of King’s, enlisting his books to improve his English.

Arcel, however, had never worked on this complicated a project, and he found himself in over his head on the $66 million fantasy film, say several sources.

Three blind screenings last October, shown before final effects work had been completed, confirmed fears that the picture was a mess. Audiences at the test screenings couldn’t understand the mythology and rated the film poorly. A classic tale of good and evil, “The Dark Tower” stars Idris Elba as the last Gunslinger, who is locked in an eternal battle with a sorcerer known as the Man in Black, portrayed by Matthew McConaughey.

Sources say the companies ultimately opted not to enlist another filmmaker (one explained it would have been too costly), but the executives from the studios remained heavily involved. Ron Howard, a “Dark Tower” producer, who had hoped to direct the film when it was set up at Universal, advised Arcel on the music, and co-writer and producer Akiva Goldsman helped wrangle the film into shape.

Arcel insists he wasn’t sidelined.

“On a film with two studios and powerful producers, obviously there is much passionate creative debate on how to work certain ideas or beats,” he said. “But I felt supported throughout, and they all looked to me for answers. If someone had jumped into my editing room and taken over — I would have left instantly.”

Rothman and Wiczyk say they were impressed with Arcel’s work, with the Sony chief saying he “hopes to” collaborate with the director on future projects. Wiczyk also hit back at claims the film was troubled.

“We shot this on time and on budget,” he said. “We didn’t go over our schedule by even a day.” Calling his company “artist driven,” he added, “We would never marginalize or remove a director or dare to edit a film.”

Sources paint a more acrimonious picture of the production, one that was enabled by the unique nature of the deal that Sony struck with MRC — a pact that allowed competing power centers to emerge. The two companies split costs, and in return MRC was granted “kill rights” on everything from the marketing campaign to the final cut of the picture. If one company didn’t like a trailer or a cut of the film, it had to be scrapped, making it difficult to achieve consensus. It’s a rare type of partnership, with the kind of sign-off that few production companies enjoy. That led to a case of “too many cooks in the kitchen,” according to one insider. King also had a great deal of input. In return for the rights to his work, he retained veto approval of almost every aspect of the film.

Sony and MRC admit “The Dark Tower” defied easy translation. The books move forward and backward in time and reference multiple genres, from gangster films to Arthurian legends. It was a struggle to combine parts of several books into an 88-minute film that appeals to both King devotees and mainstream audiences.

Sony and MRC spent $6 million on reshoots to fill in more backstory about Elba’s character’s hatred for McConaughey’s Man in Black. In addition, to better familiarize audiences with Mid-World, the film’s magical setting, five minutes of exposition were cut and a new scene was shot to combine ideas that had been sprinkled throughout the picture.

Sony’s Rothman believes that the narrative complexity will ultimately help the film connect with audiences. “It’s a fantasy film and so yes, it’s complicated; it’s intricate and ambitious, but that’s a good thing because with the complexity of the stuff on television now, theater audiences want ambition,” he said.

On social media there’s been speculation about the quality of “The Dark Tower” given that the studio moved the picture premiere from February to July, only to push its release back by an additional week. Despite the mixed buzz, “The Dark Tower” is tracking to open in the mid-$20 million range. It also has the support of an important critic. In the novels, someone who acts dishonorably is said to have “forgotten the faces of his fathers.” After seeing the film, King sent Arcel an email praising him. “You have remembered the faces of your fathers,” he wrote.