When I try to change it to 4.5, I only see 4.5.1.
When I try to install 4.5, from here, I get the following message:
So, it's already apart of the OS, but I can't select it in VS2012.
Any ideas?
.NET 4.5.1 IS .NET 4.5
Microsoft fixed a few things and added a few new features and pushed the update out. You CANNOT downgrade from 4.5.1 to 4.5.
Here is the article from MSDN: http://msdn.microsoft.com/en-us/library/ms171868(v=vs.110).aspx#v451