title: Project migration from 32bit to 64bit not successful
body: <p>I am working on a project that includes 15 projects in C++. This project was developed in 2010 for the 32bit architecture. Now, I want to port this project to 64bit.</p>
  <p>First, I compiled it with a 32bit configuration in VS2019. The code compiles successfully, but the executables generated do not work. I assume this issue may be due to compatibility issues of 32bit architecture with 64bit architecture.</p>
  <p>That's why I changed the configuration to 64bit. I added the path for 64bit libs in project properties, and replaced third party libs with 64bit versions. But when I compile the code, it fails and the error states:</p>
  <blockquote>
  <p>X files are not found</p>
  </blockquote>
  <p>When I checked external dependencies, those files are not showing there, which were there in the 32bit configuration.</p>
  <p>So, I checked the projects to which files belonged, and I found out for those projects, even though I changed their configuration, are still running in a 32bit configuration. When I change individual projects to 64bit and close the configuration manager, they change back.</p>
  <p>Can anyone tell me the reason for this, and how I can solve this issue?</p>