Under the emergency procedures, voters fill out paper ballots and poll workers drop them into orange emergency bags. The bags are to be sealed and taken to the Board of Elections at the close of voting, where staff will hand-count them before tabulating the ballots the machines processed. Poll staff were told to keep checking in voters normally while technicians worked on the hardware. Problems were reported in New Rochelle, North Salem and Ossining, where machines at St. Paul's Church rejected ballots and sent them to the bags. Brad Kennedy, a voter in Croton-on-Hudson, said his ballot was repeatedly rejected at 6 a.m.

The cause is disputed. The Westchester County Board of Elections first pointed to "the thickness of paper ballots," according to several outlets. NBC New York reports the board issued a correction less than an hour later that dropped the phrase and said only that paper ballot issues were preventing machines from accepting ballots countywide. Rep. Mike Lawler said the cause was unknown, and The Journal News reports the board had not immediately identified it.

The county board apologized for the disruption, said it is in constant communication with state officials, and said "every ballot cast will still be counted." It said the ballots in the orange bags are secure and monitored. The New York State Board of Elections said the ballots are being secured under bipartisan control and will be counted under applicable procedures. It also said there was no disruption to voting, a description at odds with the reports of rejected ballots at most sites. The state board is working with county officials on the malfunction, and the New York Attorney General's office is monitoring the situation. Attorney General Letitia James said, "Westchester voters can still safely fill out and turn in their ballots at their polling locations. Your votes will count."

The failure landed in a closely watched place. Westchester is the most Democratic part of the 17th Congressional District, where Lawler, a Republican, is defending his seat against Democratic challenger Cait Conley in a race Raw Story calls a toss-up. Westchester backed Kamala Harris 63% to 37% in 2024, while Lawler won 60% of the vote that year across Rockland, Putnam and Dutchess counties. Rockland and Putnam, which are also in the district, reported no issues.

Lawler said every scanner in the county was having problems. "However, every ballot will be counted. Stay on line and vote. Do not leave the polling place without voting," he said. Conley wrote: "There are technical issues with ballot scanners in Westchester, but don't worry: you can still vote and every vote is being counted!"

Rep. Claudia Tenney, a New York Republican, posted on X that "The Democrats in NY will do anything and everything to cheat." Conley responded that the issue is being worked on "in a bipartisan manner." Political analyst Jeff Coltin said definitive results in the Lawler–Conley race might not be available Tuesday night if the problem is not fixed quickly.