Forgot to say in last post that I also get a strange 'bug' in Steam. I think it happens at the same time as the false corrupt save issue but will have to check correlation is a completely matching one not a separate problem. When I shut game down after false corrupt save problem I can't immediately restart game (via NMM). Steam window pops up saying 'downloading Microsoft redistributable package'. This window hangs and game doesn't start. Have checked I have all x86 and x64 redistributable packages and all good. So I have to close Steam fully, restart it and I can then play the game again. Thought this might be helpful. Might just be a quirk of my system though.