The appeals ruling restrained Mary Trump and any agent of hers from distributing the book, but the court made clear it did not consider the publisher to be an agent, though that issue could be decided in further proceedings at the lower court.
"The evidence submitted is insufficient for this court to determine whether the plaintiff is likely to succeed in establishing that claim," the appeals court said.
In a statement, Simon and Schuster said it was gratified with the ruling, which it said would let Mary Trump tell her story. The publisher said the book was of "great interest and importance to the national discourse that fully deserves to be published for the benefit of the American public".
It added: "As all know, there are well-established precedents against prior restraint and pre-publication injunctions, and we remain confident that the preliminary injunction will be denied."
Mary Trump's lawyer, Theodore Boutrous Jr, said in a statement it was "very good news that the prior restraint against Simon & Schuster has been vacated".
He added that he believed a similar finding was necessary for Mary Trump, "based on the First Amendment and basic contract law".
- AP