Voters cast their ballots during early voting in Charlotte, North Carolina. Thomson Reuters Widespread issues were reported across North Carolina on Tuesday as millions of residents attempted to vote.

In Durham County, as many as six precincts reported software malfunctions with the laptops used to verify voter registration. The glitches prompted a countywide switch to using paper rolls, causing one precinct to run out of authorization-to-vote forms.

At one precinct, voting was halted for two hours when it ran out of forms, according to The Raleigh News & Observer.

The state elections board extended voting hours up to one hour at eight precincts in the county.

The issue could end up hurting Democratic nominee Hillary Clinton — nearly 40% of Durham County residents are black, one of her key voting blocs. The county voted overwhelmingly for Barack Obama in 2012.

Meanwhile, across the state, reports of missing registrations were filed by voters who said they tried to register through the Department of Motor Vehicles.

The problem arose on the first day of early voting, when the names of some voters who tried to register through the DMV didn't appear on voter rolls. A federal judge ordered state election officials to count provisional ballots from those voters, but on Tuesday, apparently not everyone was offered a ballot.

"It's seeming to us that some poll workers are not up to speed on that," Allison Riggs, senior attorney with the Southern Coalition for Social Justice, told The Washington Post. Briggs said the number of these reports could be in the thousands.

Some voting disruptions were also reported in Charlotte, North Carolina's largest city. According to The Charlotte Observer, one man said he tried to select Republican nominee Donald Trump on his voting machine 10 to 15 times before it registered his vote.

"It may have been a sensitive or slow computer, but seemed like an odd experience," he told The Observer.

A woman passes by political campaign signs in Winston-Salem, North Carolina. Alex Wong/Getty Images Polls suggest North Carolina could see one of the tightest races in the country. The state is particularly critical for Trump, as he has few credible paths to the White House without it.

Voting controversies have been a recurring theme in the Tar Heel State recently. Last week, a federal judge ruled the state needed to restore the voting eligibility of nearly 7,000 voters who had been illegally purged from registration lists.

Earlier this year, a federal appeals court struck down the state's contentious voter identification law for deliberately targeting black voters "with almost surgical precision."