However, it's not only electronic machines that are drawing concern.
In California, where officials ordered paper voting, election workers braced for heavy counts and worried about their scanners being able to tally a higher-than-usual number of votes.
In New York, old-fashioned mechanical levers make a loud thud, indicating that a voter's choice is entered, but they do not produce paper trails to reassure voters or election workers that the votes are properly recorded.
The Empire State has fought the federal laws requiring a conversion to electronic machines and is expected to be the last to switch. Even those most basic machines caused problems in at least one polling place in Manhattan, where workers said levers were broken and voters had to use emergency ballots.
Upstate New York horse racing heaven Saratoga County reportedly used electronic machines it spent thousands of dollars on, even though the state has said they don't meet its standards. And, as New Yorkers from the Adirondacks to the Big Apple cast their votes, state and local election workers, experts, and policy makers continued debating how to upgrade the old system.
In Connecticut, Missouri, and Illinois, voters are using electronic touch-screen voting machines, but those states require paper trails and audits. A handful of other states require paper trails but no audits.
In Georgia, which is relying purely on the electronic machines, election workers distributed provisional ballots because of problems with the machines.
Arkansas and Tennessee also are using touch-screen machines.
Problems also have been reported in New Jersey, which is using a combination of paper and electronic voting. The state planned to use printers to create paper trails but they could not deploy effective technology in time for Primary Day. At least one polling station had trouble firing the machines up and some voting was delayed because of it. Several media outlets reported that Gov. Jon Corzine waited more than an hour after arriving around 6 a.m. to cast a vote on one of the downed machines.