Based on the novel by best-selling author Max Brooke, the postapocalyptic war tale has had a slow transition to the big screen.
Extensive re-shoots, script rewrites, and creative issues have forced Paramount to postpone the film's release to June 2013 when it was supposed to premiere in December, according to The Hollywood Reporter.
"The footage from this film looks fantastic, but we agreed it can have a better ending," Paramount film group president Adam Goodman told Canoe.com. "Getting the ending correct is essential, and we are in that creative process. 'World War Z' is a giant summer movie and we are confidant it will be a global hit when it's released in June 2013."
Another source close to the production of "World War Z" described the work on the film as "a nightmare from top to bottom," reported THR.
Additionally, the $170 million-plus Paramount film's director Marc Forster was unable to bring his usual team with him and was instead surrounded with inexperienced and unfamiliar people.
"The director was not empowered … There was nobody that steered the ship," continued the source close to the film's production. "When you get [a director] who can't do it all … you get a struggle as to who is that singular voice. They just couldn't get it right."
"World War Z" reportedly experienced production problems early on. During filming in Hungary earlier this year, an anti-terrorism unit raided a warehouse and confiscated 85 fully functional automatic weapons. According to insiders, Pitt was furious with the crew for making the mistake of purchasing real rifles.
During an interview earlier this year, Pitt spoke excitedly about the movie's potential.
"Can we take this genre movie and use it as a Trojan horse for sociopolitical problems, and what would the effect on the world be if everything we knew was upside-down and pulled out from under us?" he asked, according to THR.
The actor added that while he was not sure how many audiences would like that film, he felt sure "World War Z" would satisfy his friends.