diff --git a/packages/material-ui/src/RootRef/RootRef.js b/packages/material-ui/src/RootRef/RootRef.js
index dc8b3d7724c3e5..5144f0db8b5f9b 100644
--- a/packages/material-ui/src/RootRef/RootRef.js
+++ b/packages/material-ui/src/RootRef/RootRef.js
@@ -67,6 +67,7 @@ class RootRef extends React.Component {
   render() {
     if (process.env.NODE_ENV !== 'production') {
       if (!warnedOnce && process.env.INTERNAL !== 'true') {
+        warnedOnce = true;
         console.warn(
           [
             'Material-UI: The RootRef component is deprecated.',
diff --git a/test/karma.conf.js b/test/karma.conf.js
index decc304fde624d..6bca2e87efabf9 100644
--- a/test/karma.conf.js
+++ b/test/karma.conf.js
@@ -55,6 +55,7 @@ module.exports = function setKarmaConfig(config) {
           'process.env': {
             NODE_ENV: JSON.stringify('test'),
             CI: JSON.stringify(process.env.CI),
+            INTERNAL: JSON.stringify(process.env.INTERNAL),
           },
         }),
       ],