(CNN) -- You could say Kathryn Jones got lucky twice.
Once when she won the lottery jackpot, though she didn't know she won. And again when lottery officials used technology to track her down to tell her she is a multimillionaire.
The 55-year-old Hamilton, Ontario, woman almost didn't believe it when lottery officials showed up at her doorstep, trying to convince her that she had bought a winning ticket more than a year ago.
"We weren't sure we wanted to let them in the house, because we weren't sure who they were," Jones said at a news conference this week announcing her prize.
Unclaimed lottery prizes usually stay that way. Some don't see lottery officials as the kind of people who would go out of their way to track down a winner.
But a unique set of circumstances -- you might even call it luck -- brought the lottery to Jones' door.
The $50 million jackpot winner (about $46.7 million U.S.) was drawn November 30, 2012. For more than a year, people claiming to the be winner came forward.
In all, said Rod Phillips, president and CEO of Ontario Lottery and Gaming Corp., 435 people claimed to be winners, only to be rejected.
Phillips told CNN affiliate CTV that each time a "winner" came forward, there was an investigation. During the course of one of those investigations, Jones' name came up as the possible true winner. That's the only reason lottery officials even thought about trying to track her down, Phillips said.
"Through our transactions database, we determined the time, date and location of the purchase," said another lottery official, Mike Hamel. "We obtained store security video, which clearly shows the identified winner purchasing the winning ticket."
Jones purchased the lottery ticket in Cambridge, Ontario, and lost it shortly afterward, CTV reported.
If it wasn't for the lottery officials tracking her down, she never would have known she was a winner. She doesn't remember what happened to the winning ticket.
"I wish I knew," she told CTV. "I honestly don't know. I have looked into my house very thoroughly, and it's not there. I'm not sure whether I threw it out by accident or what happened to it."