The claim has been his chief argument in defense of accusations he mishandled the information and imperiled US national security.
In a court appearance Tuesday, special master Raymond Dearie, the official assigned to review the documents, pushed Trump's lawyers to provide evidence for the declassification claim.
But Trump's lawyers didn't, arguing that making the evidence public could damage their defense if the case came to trial.
"As far as I'm concerned, that's the end of it," Dearie said, indicating that he was losing patience with the declassification claim.
In a ruling Wednesday, an Atlanta appeals court reinstated the DOJ's access to the classified information, and dismissed the declassification argument as a "red herring" that did not exculpate Trump even if true.