streak can result when a sensor fails. In the right place, such lines can indicate a vote for every candidate or no votes for anyone. Some offices blow compressed air over the scanners after every 200 ballots to remove dust. Software can miscount or fail to count. If it fails or miscounts drastically enough, people notice and check. Errors can happen in the scanner or at the ballot printer. Staff rarely identify the person who caused an error, and assume it was accidental, not a hack. In a 2022 election in DeKalb County, GA, a candidate who actually won appeared to lose, after votes were not counted for her in some precincts, because another candidate withdrew, and programming did not categorize votes correctly. in a 2022 election in Clackamas County, WA, scanners could not read more than 100,000 ballots on which the ballot printing company had printed a blurred bar code. The ballots needed to be hand-copied by teams of two onto correctly printed ballots. The problem was discovered May 3, for the May 17 election, and was not corrected until after the election. in a 2022 election in Lancaster County, PA, scanners could not read 22,000 ballots on which the ballot printing company had put the wrong identification code. The ballots were hand-copied by teams of three onto correctly printed ballots. The state does not let mailed ballots be scanned before election day, so the problem was only discovered on election day. in a 2021 election in Williamson, TN, precinct scanners had two errors: They misread QR codes, mistakenly classifying some ballots as provisional and not to be tallied, then kept that not-to-be tallied classification for later ballots, so large numbers of ballots were not included in precinct reports at some precincts. They were re-scanned correctly on a central scanner and checked by a hand-tally. The county rented another brand for the 2022 elections. In a 2021 primary in New York City, 135,000 test ballots were not removed from the database and were included in preliminary counts for the mayoral primary. They were discovered because totals were higher than the number of voters, and corrected by removing them from the count. in a 2021 election in Lancaster County, PA, scanners could not read 12,300 ballots on which the ballot printing company had put the wrong identification code. in 2020 elections in Collier and Volusia Counties, FL, the election's optical