C++ Issues with windows.h, Illegal declaration of anonymous 'struct' in vs17 - c++

Question

When the following code is compiled I get these errors:
Error C2467 illegal declaration of anonymous 'struct'
C:\Program Files (x86)\Windows Kits\10\Include\10.0.18362.0\um\winnt.h 12723
Error C2133 '_IMAGE_POLICY_METADATA::Policies': unknown size
C:\Program Files (x86)\Windows Kits\10\Include\10.0.18362.0\um\winnt.h 20801
Error C2467 illegal declaration of anonymous 'struct'
C:\Program Files (x86)\Windows Kits\10\Include\10.0.18362.0\um\winioctl.h 4327
The code:
#include <iostream>
#include <chrono>
#include <thread>
#include <windows.h>
using namespace std;
int main()
{
std::cout << "Timer!\n Enter a number of seconds: \n";
int n;
std::cin >> n;
std::this_thread::sleep_for(std::chrono::milliseconds(n*1000));
std::cout << "Timer is up";
std::cout << '\a';
return 0;
}
These errors do not occur when windows.h is removed, as I am somewhat new I could be making a basic mistake however a lot of tutorials use it and it simply does not want to work. I have used a very basic snippet of code so that it is easier to determine whether it is a mistake on my behalf or an error somewhere else.
Windows 10, Visual Studio 2019 16.2.5

Answer 1

As #FrançoisAndrieux mentions in the comments, the windows.h header requires not enabling the "Disable Language Extensions" option under C/C++ -> Language (switch /Za).
However, if you are only looking to compile simple code that does not require windows.h, simply remove it. You can write:
#include <iostream>
#include <chrono>
#include <thread>
int main()
{
std::cout << "Timer!\n Enter a number of seconds: \n";
int n;
std::cin >> n;
std::this_thread::sleep_for(std::chrono::milliseconds(n*1000));
std::cout << "Timer is up\a";
return 0;
}

Answer 2

Both of the two error descriptions are related to that switch which is as #Acorn said. The link below is Microsoft's official document. If you can't solve your problem in this way. Maybe you need to consider using VS tool to repair your environment.
https://learn.microsoft.com/en-us/cpp/error-messages/compiler-errors-1/compiler-error-c2467?view=vs-2015
https://learn.microsoft.com/en-us/cpp/error-messages/compiler-errors-1/compiler-error-c2133?view=vs-2015