The opening of two art shows today at an Upper East Side gallery known for its extensive Renaissance and Baroque art collections, Salander-O’Reilly Galleries, has been indefinitely postponed and may be cancelled, the gallery’s owner, Lawrence Salander, told The New York Sun.

At 3 p.m. yesterday afternoon, Mr. Salander said his partner in the show, Clovis Whitfield, a London art dealer, told him he had decided to withdraw his paintings from the show, including a Caravaggio painting, “Apollo the Lute player,” which the two aimed to sell for $100 million.

Mr. Whitfield told the Sun he regretted the decision, but that in this “uncertain situation” he couldn’t continue to be involved in the show.

On Thursday, a state Supreme Court judge issued a restraining order against the gallery that prevented any of the paintings from leaving the building and shut down the gallery until Monday. Stuart Slotnick, an attorney who is representing a company that is suing the gallery, Renaissance Art Investors, filed the order against Mr. Salander, he said.

The gallery has faced as many as 15 lawsuits in the last year charging that Mr. Salander does not pay back his investors by set deadlines, and in some instances instead pays with pieces of art.

“We were not quite sure if the gallery would stay open for the show,” Mr. Whitfield told the Sun. “We were very concerned for the welfare of our pictures and those of our clients.”

Renaissance Art Investors had “hundreds” of pieces of art in the gallery, some of which was shown at the exhibition, Mr. Slotnick said. “We wanted to protect the artwork from being taken out to places that we weren’t aware of,” he said. “Look at all the lawsuits. Those allegations gave us great concern.”

Mr. Salander said the show is the first of 580 over 31 years that he has postponed.