County election director Howard Jackson says all the uncounted ballots came from a single machine used by absentee voters at the election office.
“I can’t understand how that happened,” Jackson said.
He said the uncounted ballots would not have changed any of the outcomes.
It was the first countywide election since last November’s general election, when precincts did not have enough voting machines, leaving some people in line up to seven hours.
Hundreds of ballots were not counted.
The Nov. 5 election included the race for Columbia mayor and a countywide property tax increase for libraries.
Jackson would not say Thursday who was responsible for the mistake.
He sent a letter to County Administrator Tony McDonald and attended a closed-door meeting Thursday of the Elections & Voter Registration Board.
Elections board chairman Allen Dowdy said the meeting focused primarily on personnel matters.
“We feel that the election overall went good,” Dowdy said. “Of course, we did have some glitches as have been indicated and we are continuing to work hard to make this perfect as soon as possible.”
Jackson apologized to anyone whose vote was not counted.
He promised the problems will be corrected by the time Columbia voters go to the polls Dec. 3 to decide whether to change forms of government to a strong mayor system.