Weird Error List using VS2019

[CodeGetter]

Have tried to compile several C++ apps downloaded from Github and they all compile with numerous errors all referring to external dependencies. So that got me thinking, a single compile failure; look deeper. Two compile failures something weird is going on. So now try and eliminate.

Created a new C++ Console Hello World project and immediately did a build. Error out: 917 errors all pointing to external dependencies e.g. 'constexpr' is not valid here File type_traits and so on. Right! this should not be happening!
The toolset used is 14.24.28314 and the include directories are pointing to ..\10.0.16299.

My guess that there is a conflict going on (as if C++ is being compiled as C#) and unfortunately I cannot see the wood for the trees. I have checked all the usual suspects Tools:Options and examining the compiled output but no clues there. Also completed a VS2019 repair! Clang components are not installed

So if a member could either have an Eureka moment or give me some pointers on what else to try, I would be most grateful as this problem is to be honest driving me nuts. Source has not been included as it wouldn't be relevant to problem resolution.

Thanks in advance

[coder777]

'10.0.16299' is most likely the windows sdk version. It seems rather old (I have 10.17... and higher).

Thus there might be a version conflict. Either selecting the latest version may help or you need a clean reinstall.