Talk about a disappearing act: Harry Potter just vanished from the 2008 movie schedule.

Warner Bros. shocked fans around the globe on Thursday when it announced that “Harry Potter and the Half-Blood Prince,” the sixth installment in the massively successful film franchise about a young wizard and his friends, will not hit theaters in November as planned. The film will instead be delayed eight months and arrive on July 17, 2009, according to Alan Horn, Warner Bros. president and chief operating officer.

The move was made in the wake of the writers' strike and to exploit the potent summer film market in the same fashion as the last “Potter” film, which grossed $292 million in U.S. theaters after its July 11 release last year, Horn said.

"We are still feeling the repercussions of the writers' strike, which impacted the readiness of scripts for other films — changing the competitive landscape for 2009 and offering new windows of opportunity that we wanted to take advantage of," Horn stated in the release.

That may be, but any scheduling change for a blockbuster release stirs intense scrutiny in Hollywood, and across the industry Thursday there was speculation that the move reflected some significant problem with the London-based production or with some other part of Warner’s release schedule.

The major Warner's film already scheduled for next summer is “Terminator Salvation,” a darker reboot of the killer-robot franchise, which stars Christian Bale. That movie is now shooting in New Mexico.

Warner is riding high right now with one of the great modern success stories in Hollywood, “The Dark Knight,” the Batman film that stars Bale as well as the late Heath Ledger. The grim super-hero movie has now gone north of $450 million in the U.S. since its release July 18. The film is now second only to “Titantic” as the top-grossing film in history.