I don't know if this is the same bug that Aragorn was trying to report, but I just lost my savegame in v.704. The last time I saved & exited, I encountered the computer-crashing blue screen (sadly, a fairly frequent occurance - but I assume that you guys are working on it, since it's been reported many times). This has never before affected the savegame... but this time it did. When I went back into the game, the savegame description was "day 1 (0:00), incorrect file type".
If it helps to find this problem, I'm happy to provide you with the corrupt savegame file.
BTW, looking in the folder, I see that there is also a file called "last_savegame_backup.sav". I assume that if I rename this file to sg0x.sav, I'll be able to recover the character from the corrupt savegame?