Some computer problems, as well as human ones, drew complaints across the country as millions of Americans went to the polls.
One Pennsylvania voter highlighted a problem with voting machines on YouTube, complete with video, in which a touchscreen changed his choice from President Barack Obama to Republican Mitt Romney.
"I initially selected Obama but Romney was highlighted," the man wrote. "I assumed it was being picky so I deselected Romney and tried Obama again, this time more carefully, and still got Romney."
This was not the first allegation of foul-ups with electronic machines.
In Ohio, some Republicans claimed machines were changing Romney votes to Obama, while Democrats accused Republican state officials of installing untested "experimental" software at the last minute.
To make matters worse in the crucial swing state, some voting machines were malfunctioning in parts of the Cleveland area, said The Plain Dealer, which quoted election officials as saying ballots would be counted even if scanning machines were down.
In New Jersey, a late decision to allow voters displaced by superstorm Sandy to cast ballots by email caused confusion and frustration.
"Oh no! email box for Essex County Clerk's box is full. No one can email in their ballots," said a tweet from one resident.
Betsy Morais, a writer for The New Yorker, found similar glitches. Her email bounced back.
"I tried again, and once more the message failed. It took three tries to get through to the clerk's office by phone. 'Oh, you can just go online to our Web site to find the ballot and fax it in,' I was told. I was confused."
Another source of confusion was a last-minute modification, hours before polls opened, stipulating that voters needed to mail in paper ballots as a verification of the email vote.
The news website Buzzfeed reported that in two major New Jersey counties, email addresses advertised on the county clerk's website were down, and that one county clerk posted his hotmail address on Facebook for voters.
That in turn prompted a Facebook response from one netizen, who said, "Using your personal hotmail address for official use is very dangerous and quite likely illegal."
In Benton County, Arkansas, officials ran out of paper ballots, local television reported. Voters, who normally have an option to vote electronically or on paper, only had the e-vote option.
Barbara Arnwine of the Lawyers' Committee for Civil Rights Under Law said that in Pennsylvania, some voters were told they needed photo identification, even though state law has no such requirement.
"This is the fault of the Pennsylvania state government," Arnwine said, noting that Pennsylvania passed a voter ID law, but a court blocked it from being enforced.
An "election protection hotline" set up up the lawyers' committee said voters complained of "chaos" in some Florida precincts, with waits of up to five hours.
In Palm Beach County, Florida, epicenter of the 2000 punch card debacle, local television reported voting was delayed by a printing machine malfunction.
Elsewhere in Florida, the Tampa Bay Times reported that hundreds of voters received automated "robo-calls" telling them the election was Wednesday.
An official told the paper a glitch in the phone system allowed the calls to go through early Tuesday, telling voters the election was "tomorrow."
"We stopped it immediately when we found out about it," Pinellas County elections supervisor spokeswoman Nancy Whitlock told the newspaper.
A similar glitch was reported in the US capital city Washington.
The Arizona Republic reported that robo-calls directed voters to the wrong polling stations, and that Democrats claimed it was an intentional effort by Republicans to misdirect people amid a tight Senate race.
