diff --git a/packages/react-error-overlay/src/utils/unmapper.js b/packages/react-error-overlay/src/utils/unmapper.js
index 60b2bee432b..524b5258752 100644
--- a/packages/react-error-overlay/src/utils/unmapper.js
+++ b/packages/react-error-overlay/src/utils/unmapper.js
@@ -56,7 +56,7 @@ async function unmap(
     }
     let { fileName } = frame;
     if (fileName) {
-      fileName = path.normalize(fileName);
+      fileName = path.normalize(fileName.replace(/[\\]+/g, '/'));
     }
     if (fileName == null) {
       return frame;