A former executive director of the school, Jennifer Sherwood Gaul, said recently that she had warned the board that “selling the building will kill the school.” And a former business manager, Andy Huber, said that crucial decisions were made in haste. “They could have just waited until we got a better offer” for the building, Mr. Huber said.

The board president, Jeffrey Schlosser, disagreed, and said in an interview that the shutdown was “not a dissolution of the school.” He called it “a ceasing of operations so we can get the debt monkey off our backs.” In a recent conversation, he disputed that Ms. Gaul warned against the move and that Mr. Huber counseled waiting for another deal.

Mr. Schlosser sees a future for the school in music therapy, which “does not require a location.” Such a focus would involve “us going to hospitals or people’s homes,” rather than bringing students to a school facility for lessons.

For many of its alumni and friends, the school was as much about bricks and mortar as it was about pitch and tempo. Nearly everyone associated with the school used the word “charming” to describe the East 52nd Street building. It sat on a block in a neighborhood that was once home to Katharine Hepburn, Greta Garbo and E.B. White. Its recital hall was named for another long-ago neighbor: Alma Gluck, a Metropolitan Opera star and early recording sensation.

Affection for the place, though, never obscured its many drawbacks. Its studios were not soundproof, the heating system was less than reliable and the building was inaccessible to people who could not manage steps. Sometimes administrators would go outside to help parents carry strollers up the stairs leading to the tall red front doors. Inside, there was no elevator, and the building was expensive to maintain. Helen du Bois, a board member for nearly 30 years beginning in the 1960s, said that “there was a continual drain on our resources to keep having to fix it.”