title: I have a working React build on a live server, I can not get it to work locally
body: <p>I'm not entirely sure where to begin on this question, so bare with me --
  I have the copy of a live version of a React.js build.  I am attempting to set it up locally so I can make changes.
  I cannot get it to work.</p>
  <p>I have tried the following:
  Deleting the node_modules folder and reinstalling each module in the package.json file one at a time with the version in the package file.  Doesn't work.
  Installing the dependencies and updating them all from an npm install (overarching).</p>
  <p>Neither seems to help.</p>
  <p>I turned on the debugging stuff that the previous developer put in and everything they are checking for checks out.</p>
  <p>I can not make the app behave locally.  I have spent days trying to debug.
  It connects to the server. I have XAMPP installed and the folder for the app is in the htdocs folder.
  The one error I keep getting (locally, not live) is the &quot;Can't perform a React state update on an unmounted component.&quot; error.</p>
  <p>All I want to do is work on this application.  It's about 2 years old, I didn't write it, and the person who did is unavailable.</p>
  <p>I know this is a vague question, but I have no idea what to do next.</p>
  <p>Does anyone have any suggestions?  I feel like I'm missing something.</p>