The film took three months to film and has run aground in the editing room — for three years.

by John Horn

“You Can Count on Me” was the kind of Hollywood arrival that every aspiring filmmaker dreams about.

Kenneth Lonergan’s 2000 directorial debut about two siblings’ splintered relationship was a solid art-house hit, the film helped launch the career of costar Mark Ruffalo and was nominated for two Academy Awards — lead actress for Laura Linney and original screenplay for Lonergan.

It was hardly surprising, then, that in early 2005 Fox Searchlight and financier Gary Gilbert (“Garden State”) were eager to back Lonergan’s second turn behind the camera, deciding to co-finance his complex account of a young girl’s grappling with guilt and adolescence, “Margaret.”

But although “You Can Count on Me” seemed blessed at almost every turn, “Margaret” has turned into a nightmarish production that has devolved into a bitter court fight. Despite “Margaret’s” initial promise, it is now uncertain when Lonergan’s movie, which was filmed more than three years ago, will ever make it to theaters.

Movie studio shelves are filled with troubled projects that have been put on hold for any number of reasons, but rarely do they involve someone of Lonergan’s standing working with such quality actors (“Margaret‘s” cast includes Ruffalo, Matt Damon and Anna Paquin) and an all-star producing team of Oscar winners — Scott Rudin ( “No Country for Old Men”) and the late Sydney Pollack (“Out of Africa”).

More unusual still is why, according to one of the film’s two lawsuits, “Margaret” hasn’t come out: Lonergan can’t finish the film.

Because of the litigation and a confidentiality agreement among the lawyers, all of the principals central to the film declined to be interviewed for this story. But conversations with a dozen people close to or familiar with the production, all of whom spoke on condition of anonymity, painted a picture of an endless post-production cycle that left Lonergan and Gilbert clashing and Fox Searchlight sitting on what might be an unreleasable movie.