I still struggle with this issue. Have tried to load game without any mods and basically only playing Bohemia provided missions/campaings, but still crash when loading a savegame. It only fails when loading a save game though. I haven't been playing for a month or so kind of asumes that recent Arma 3 update has something to do with this as I ran it without problems last month.
Have tried to downgrade Nvidia drivers and reset the Arma3.cfg file.
Any ideas would be great :)
Can also add that prior to getting the Unable to init dxgi message I get the following error message: Cannot load 'C:\Users\Petter\Documents\Arma 3\Saved\Steam\XXmissionnameXX\save.arma3save'