Well, in my experience is more than a 2-hour window. As I said before my first corrupt savegame is the 20/12 at 19:16 (GMT+1) and my last corrupt savegame is the 20/12 at 22:59 (GMT+1) so its a 4 hours window (More people are speaking on the forums about 6 hours. Well, it all depends, if you didnt closed the game in 6 hours or left the PC on for a longer period, you'll have more time difference between the first and the last corrupt files).
And for people like me, who overwrite savegames (I have always 5 savegames + the autosaves, but never more than that, and in this case my autosaves are corrupted also), I'm speaking actually of a loss of 57 hours of gameplay (Not going to restart after 57 hours playing) so I have 0 desire to start again the game if they don't solve it.
That is odd. My quicksave b4 the patch does still work, but i have an additional quicksave after that and that does not work (and some autosaves).
My savegames are:
Atherios (9cae2cb5-c6e4-4aa8-8d61-29faa132a0a7) (LAX-123ABCDEFGHI) autosave_0.savegame
Atherios (9cae2cb5-c6e4-4aa8-8d61-29faa132a0a7) (LAX-123ABCDEFGHI) autosave_1.savegame
Atherios (9cae2cb5-c6e4-4aa8-8d61-29faa132a0a7) (LAX-123ABCDEFGHI) autosave_2.savegame
Atherios (9cae2cb5-c6e4-4aa8-8d61-29faa132a0a7) (LAX-123ABCDEFGHI) quicksave.savegame
Atherios (ArchipielagoLlamaExtinguida) (9cae2cb5-c6e4-4aa8-8d61-29faa132a0a7) (LAX-123ABCDEFGHI) (930262135).savegame
Atherios (ArchipielagoLlamaExtinguida) (9cae2cb5-c6e4-4aa8-8d61-29faa132a0a7) (LAX-123ABCDEFGHI) (939966184).savegame
Atherios (FuertePortillo) (9cae2cb5-c6e4-4aa8-8d61-29faa132a0a7) (LAX-123ABCDEFGHI) (934139199).savegame
Atherios (RuinasdePokoKohara) (9cae2cb5-c6e4-4aa8-8d61-29faa132a0a7) (LAX-123ABCDEFGHI) (931982171).savegame
Atherios (Tikawara) (9cae2cb5-c6e4-4aa8-8d61-29faa132a0a7) (LAX-123ABCDEFGHI) (931367016).savegame
Since it says that I'm missing the LAXH & LAXI, I'm sure that the problem with the saves is that all of mine ends in LAX-123ABCDEFGHI (The HI part). I dont have any savegame without it (Checking at C:\Users\usuario\Saved Games\Pillars of Eternity II).
Maybe I have just bad luck or did something wrong when I unisntalled and reinstalled later =(
EDIT: Everything solved with the hotfix. Congratulations on your job =)