Some had an address change. Others just decided to show up Tuesday at a polling site and vote even though they have never registered in Douglas County.
Such voters were among about 3,000 for whom ballots were marked provisional by the Douglas County Clerk's office.
The county's board of canvassers, which is made up of the three members of the Douglas County Commission, will review the provisional ballots beginning at 9 a.m. Monday in commission chambers at the courthouse, 1100 Mass.
"I expect this will go smoothly because we do it after every election," Commission Chairman Charles Jones said of the canvassing. "I don't anticipate this being a difficult process."
The board will decide which ballots to count and which ones to discard based on the recommendations of the clerk's office.
Even with a relatively large number of provisional ballots, no election outcomes are expected to change. But the possibility is there.
One of the closest races Tuesday night was for the 10th District House seat, which pitted Democratic incumbent Tom Holland against conservative Republican Rich Lorenzo. Holland won Tuesday with 50 percent of the votes while Lorenzo had 48 percent.
But part of the 10th District spills into Franklin County. On Friday, Lorenzo managed to add 24 votes during Franklin County's canvass. That brought Lorenzo's overall total to 5,040. Holland also picked up 16 votes in Franklin County on Friday, bringing his overall total to 5,333 votes.
Marni Penrod, deputy of elections for Douglas County, said she didn't have a tally from past elections, but said the canvassing board would be dealing with more provisional ballots than in previous elections.
"But it shouldn't impact the board greatly because we will have the ballots broken down into categories," she said.
Since the election, county clerk employees have been going through the provisional ballots and dividing them into two broad categories: those recommended for approval and those not.
"Ones that we would recommend to count would be if there was a change of address, a name change or if they didn't have identification but brought it in later," Penrod said. "Some that we would recommend not to approve would be if they've never been registered voters in Douglas County. We did have some."
Clerk's office employees have reviewed each provisional ballot since the election, Penrod said.
It takes time, she said. Workers must sort through information to decide whether a ballot should be counted, and everything gets checked -- including the signature.
"Each ballot is its own little investigation," Penrod said. "You get some variety, but it can become a little tedious at times when you're researching a ballot and have a whole stack in front of you left to do."