I just purchased the game and its sequel off Impulse, and almost immediately encountered this bug. In the very first broken-down town outside the starting area, there is an Inn with a locked door upstairs. I saved my game before attempting to pick the lock, and after failing and trying to reload that save game, the game crashed to desktop. When I started it back up and loaded the game successfully, I managed to pick the lock - when I tried to save the game after that, I was told the quicksave could not save because of a DELDIR error, and the save list was blank.
I tried to make a manual save and it seemed to succeed, but it still does not show up in the save game list (which is still blank). When I try to load the save position where I put the now-invisible manual save, sometimes it loads, and sometimes it crashes to desktop.
Very disheartening to encounter this right away, and then to come here and read that somebody else is also having the problem but that it's being referred to as "extremely rare". Maybe it is, but it's also my first experience with a game I just bought, and doesn't lend me much confidence towards the rest of it.
EDIT: The advice in this thread
to delete the quicksave directory did work, but it also happened again after only two more game saves. Disappointing bug to have to deal with.