The Detroit City Clerk's office is already warning voters that results from the August 6 primary may be delayed.
City Clerk Janice Winfrey said they are expecting a higher than normal amount of write-in votes, which take longer to check.
"The write-in process is a very manual process," said Winfrey. "It is going to take a bit longer than we're used to, but we'd like to think we'll have some good, unofficial, results by some time around midnight or 1 o'clock (the next morning)."
Detroit mayoral candidate Mike Duggan launched a write-in campaign after being removed from the ballot after a court challenge.
Winfrey said there are other write-in campaigns as well from candidates hoping to land a seat on the Detroit City Council.
Winfrey said her staff is preparing as much as possible for the write-ins.
"You train, you train, and you train," Winfrey said.