Donald Edwin Pringle, 61, was last seen on the afternoon of Saturday, August 28, 2010, walking alone on Great Northern Road near Second Line East in Sault Ste. Marie, Ontario. He was described as a white male, 5 feet 11 inches, 190–200 pounds, with short receding white hair, blue eyes, and a moustache. He was wearing a light blue polo shirt or sweater and shorts and may have been wearing a cowboy hat; he was not carrying anything.

Pringle lived with bipolar disorder and required medication; reports note that without his medication he could become agitated and aggressive, a detail that heightened concern after his disappearance. The Sault Ste. Marie Police Service opened an investigation (incident number SM10022019) and asked the public for information. By late 2014 he remained listed as missing and his file was one of four long-term missing persons files with the service; the most recent tips then had come about a year and a half earlier and had not produced a breakthrough.

The circumstances of his leaving on that routine walk remain unexplained. If anyone knew Donald, saw him on August 28, 2010, or has information that could help, please come forward to the Sault Ste. Marie Police Service.