A judge in Nevada has rejected a request by Donald Trump's lawyers to have the ballots from four early voting sites preserved in case the campaign wanted to contest them later.
Campaign lawyers had questioned the legality of the polling sites staying open two hours beyond their designated time on Friday, and asked that the ballots cast during those hours be set aside.
Most Americans cast their ballots on Tuesday, but Nevada is one of several states that also allows early voting.
Officials with Clark County had told CNN that the poll times were not extended, as the Trump campaign alleges, but that people who were already in line at the time of the official close were allowed to vote.
The four polling sites were in areas with a strong minority population, such as Hispanics, a demographic that Mr Trump has not proved popular with.
Judge Gloria Sturman told the Trump lawyers that their petition was without merit and could potentially violate the privacy of the poll workers, according to CNN.
Mr Trump and Democrat Hillary Clinton are in a close contest to win Nevada in Tuesday's election after a long and contentious campaign.
David Bossie, Mr Trump's deputy campaign manager, said on MSNBC that the lawsuit was not aimed at suppressing the Hispanic vote.
"This is a lawsuit about the rules of the game," he said.
Clark County spokesman Dan Kulin said the lawsuit asked the county to preserve records, "which is already required by law for us to do that."