Error: You are debugging a Release build of X.dll
<h3>Background</h3>
<p>I have an ASP.NET MVC application project, along with various other projects within a Visual Studio solution. The different projects use various versions of the NPoco library as follows:</p>
<ul>
<li>The MVC project includes a version of NPoco through NuGet.</li>
<li>Some other projects include a (probably different) version of NPoco through a reference to a DLL (not the DLL provided through NuGet).</li>
<li>One of the projects is the source code of a version of NPoco with some alterations made.</li>
</ul>
<p>I'm using Visual Studio 2015 Update 3 14.0.25422.01.</p>
<h3>Error</h3>
<p>For some reason, when I launch this application in the debugger using the normal Start Debugging command in Visual Studio, it launches, but it also produces the following warning:</p>
<p><a href="https://i.stack.imgur.com/1r09x.png" rel="noreferrer"><img src="https://i.stack.imgur.com/1r09x.png" alt="You are debugging a Release build of NPoco.dll. Using Just My Code with Release builds using compiler optimizations results in a degraded debugging experience (e.g. breakpoints will not be hit)." /></a></p>
<p>If I press <strong>Continue Debugging</strong>, everything seems to still work as usual, including breakpoints.</p>
<p>This problem only started happening recently.</p>
<h3>Question</h3>
<ol>
<li>Anyone know what caused the above error?</li>
<li>Do I have something misconfigured?</li>
</ol>