Larian made very clear from the beginning (launch alpha) that savegames between updates are not supported. It's quite impossible to do so ... this isn't the final product where only small fixes are added, sometimes the environment, quests, items, characters, ... change radically. Even with completed games it occured that a patch implied previous savegames would be incompatible.
So far I went through the alpha twice ... just one lost savegame, not too frustrating.
