That is not good. For some reason the game was not successfully completing the save process.
The game saves files to a temporary folder before moving them to a folder without the .tmp extension. This is to prevent a working save from being damaged if there is a problem during the save process when overwriting an existing save.
In Windows Explorer, browse to the '..\Beyond Divinity\savegames' folder, and compare the number of files in the .tmp folder to working saves from a similar point in the game. Depending on the file, missing files might be replaceable with corresponding ones from the next most recent working save, though this might cause other problems. Depending on where is the save process the problem occurred, one or more of the files in the save may be corrupt.
Saved games - ".tmp" extension after prob; LOST!Are you shutting down all non-essential programs (especially anti-virus) before starting the game?
Did you install the latest service pack and critical updates for windows, and update your drivers?