The opera festival, which is held in late July and August in Bregenz in Vorarlberg, is usually officially opened by the Austrian president, but the court's ruling means that Alexander Van der Bellen, who won by a narrow margin in May - cannot be sworn in on July 8th.
His rival, Norbert Hofer of the Freedom Party (FPÖ), will have another shot at becoming the EU's first far-right president.
The festival is due to open on July 20th. Its famous floating stage, the Seebühne, on the shores of Lake Constance has even featured in a James Bond movie (Quantum of Solace), and it lures huge crowds every summer.
In the absence of a president, one of the three parliamentary presidents - who are Doris Bures (SPÖ), Karlheinz Kopf (ÖVP), and Nobert Hofer - would normally assume any presidential duties. However, it's been decided that they will not undertake any festival openings or state visits in the interim period before Austria's next president is sworn in.
Three weeks before the festival opens one of its highlights - Puccini's opera Turandot - is already almost booked out, with only 30 percent of tickets remaining.