Saved game suddenly only works in Steam?

Hi there

Ive got a game ive been playing for about a year now. Yesterday i tried to load my saved game but kept getting the message 'saved game not loaded'. Or words to that affect.

As a desperate measure I logged into Steam and the game loads. Does anyone have any idea why this would suddenly happen, or any ideas how to get my game to load normally? Its not a huge issue to have to login to steam every time but just seems a bit unnecessary and odd that this would suddenly happen.

Cheers