Hey guys,
So I had this problem too and I could not figure out what happened to my game that I had over 100 hours. The game looked like I was starting from scratch, none of my saved houses or people were there. So what I did was open up my documents ea > saves folder and I moved out that whole folder onto my desktop and then open up the game and created a brand-new family and saved it and exited the game. Then I went back to my desktop copied the most recent save from my old saves folder (including the .ver files) that we're not working and pasted it into the new saves folder in the ea > the sims 4 > saves folder. The slot_00000004.save file that wasn't working I deleted it and then I changed the file name of the first save.ver0 file to just ".save". When I open my game again my family was in there exactly how it was when I had last saved it. So it worked!!!