LOS ANGELES — Often film sequels are slam dunks at the box office, a seamless continuation from where a previous hit left off.

But as the new installment of the 15-year-old franchise “Men in Black” proves, getting to the big screen isn’t always a cakewalk.

One of the most troubled productions in recent Hollywood memory, Sony Pictures’ latest movie in the Will Smith-Tommy Lee Jones sci-fi-comedy franchise encountered multiple script rewrites, a discontented star and a three-month production shutdown as writers and studio executives scrambled to fix a project that nearly fell apart.

By the time it was over, the studio had run up a tab of nearly $250 million — making “Men in Black 3” one of the most expensive releases of the summer.

The film known as “MIB3” faces formidable marketing challenges given that the last sequel came out a decade ago. That means an entire generation of youngsters has never seen an “MIB” in theaters, and the bar for summer event pictures has risen considerably by such high-octane spectacles as current mega-hit “The Avengers.”

Nonetheless, Sony and the filmmakers are confident that their 3-D movie will lure families, fans of Smith, and those with fond memories of the franchise — an optimism backed up by pre-release research. Regardless of its commercial fate, the rocky production path of “Men in Black 3” shows that, contrary to the common perception, sequels are neither simple nor safe bets.

“With something like ‘Men in Black,’ a sequel is actually more difficult than the original,” said Walter Parkes, who has produced all three of the films. “The challenge is to be fresh and original but also deliver on the core values of the franchise.”

When “Men in Black 2” came out in 2002, it grossed nearly $150 million less than the 1997 original and was panned by both critics and fans, leaving a sour taste for many moviegoers. Even the filmmakers acknowledged the last movie was flawed.

It was a family trip to Southeast Asia about three years ago that convinced Parkes “Men in Black” still resonated around the world when he spotted locals watching the original movie on TV in an airport. With Smith and the other talent lined up and a sizable New York City tax credit that was available only before the new year, Sony rushed the movie into production despite not having hammered out all the plot elements. To accommodate the rewrites, a holiday break that was intended to last two weeks was extended to March.