Sporadic problems were reported Tuesday at polling places around the country, including a confrontation in Pennsylvania involving Republican inspectors over access to some polls and a voting machine that lit up for Republican Mitt Romney even when a voter pressed the button for President Barack Obama.
One Florida elections office mistakenly told voters in robocalls the election was on Wednesday.
Although the majority of complaints were simply extremely long lines, the Election Protection coalition of civil rights and voting access groups said they had gotten some more serious calls among more than 40,000 received on a toll-free voter protection hotline.
"It's already started and it's busy," said Barbara Arnwine, president of the Lawyers Committee for Civil Rights Under Law.
In Philadelphia, the Republican Party said 75 legally credentialed voting inspectors were blocked from polling places in the heavily Democratic city, prompting the GOP to obtain a court order providing them access. Local prosecutors were also looking into the reports. Democratic Party officials did not immediately return a message seeking comment.
Also in central Pennsylvania, officials said the voting machine that switched a person's vote from Obama to Romney has been recalibrated and is back in service.
Pennsylvania Department of State spokesman Ron Ruman says the Perry County voter notified elections officials of the problem after trying to cast his ballot Tuesday. Video of what Ruman called a "momentary glitch" was widely viewed on YouTube.
Pennsylvania was also the scene of what a state Common Cause official called "widespread" confusion over voter ID requirements. The state this year enacted a new photo ID requirement but it was put on hold for Tuesday's election by a judge amid concern many voters would not be able to comply on time.
Barry Kauffman, executive director of Common Cause in Pennsylvania, said election workers in many places were demanding IDs even though they are not required. It was unclear, however, just how many voters may have been turned away or discouraged.