NEW YORK >> The Woodstock 50 festival is back on after a judge said an ex-investor can’t singlehandedly cancel the anniversary extravaganza.

But Manhattan judge Barry Ostrager today declined to order the backers to put about $18 million back into the festival. The conflict is poised for arbitration.

The order came after a falling-out and dueling claims about whether the festival would happen. It’s planned for August in central New York.

Investor Amplifi Live announced a cancellation April 29. The company, part of Japanese marketing firm Dentsu, said organizers made a mess of planning and the event couldn’t safely go forward.

Organizers’ group Woodstock 50 LLC retorted the show was a go but said Amplifi was undermining it and had snatched $18 million in funds. Amplifi said it reclaimed its own money.