A group of hillwalkers got lost after magnetic interference from a mobile phone caused their compass to point in the wrong direction.
Mountain rescuers are warning walkers to be careful following the recent incident in mountains west of Glen Shee in Aberdeenshire.
Strongly magnetic jacket buttons may also have the same effect, according to Mountaineering Scotland.
Mountain safety adviser Heather Morning said: "We have reviewed the circumstances of a recent incident in the mountains east of Glen Shee, which involved hundreds of hours of rescue personnel hours and police time.
"A group of walkers were caught in low cloud and headed east instead of west, becoming totally disoriented and ending miles away from a road.
"Fortunately, no-one was hurt - just pride dented - but it could have turned out so much worse had mountain conditions been more severe.
"The reason for the error was the compass.
"It had been stored in a pocket next to a mobile phone in a case which had a magnetic closure on it, and the magnet had reversed the polarity of the compass needle, so that the north arrow pointed south."