I'm using Windows 10 Pro and I finally got Fallout 4 to run in full screen and also able to save and load games. Fallout 4 now runs with out glitches so far ( a few hours of game play and a bunch of saves ).
I launched the game from This PC>Local Disk (C:)>Program Files (x86)> Steam > steamapps >common > Fallout 4. I right clicked on the Fallout 4 and ran as administrator. When I did this the game launched and I unchecked the window mode and selected the resolution I needed . The game has been glitch free since, Hope this works for others that have not been able to save or just been able to play the game,