diff --git a/packages/shared/ReactFeatureFlags.js b/packages/shared/ReactFeatureFlags.js
index 43cbe66ea47a1..3ed8f45f9a433 100644
--- a/packages/shared/ReactFeatureFlags.js
+++ b/packages/shared/ReactFeatureFlags.js
@@ -110,7 +110,7 @@ export const enableUseEffectEventHook = __EXPERIMENTAL__;
 // Test in www before enabling in open source.
 // Enables DOM-server to stream its instruction set as data-attributes
 // (handled with an MutationObserver) instead of inline-scripts
-export const enableFizzExternalRuntime = true;
+export const enableFizzExternalRuntime = __EXPERIMENTAL__;
 
 export const alwaysThrottleRetries = true;
 
diff --git a/scripts/rollup/bundles.js b/scripts/rollup/bundles.js
index b5755725124aa..20af2f1fa1205 100644
--- a/scripts/rollup/bundles.js
+++ b/scripts/rollup/bundles.js
@@ -328,7 +328,7 @@ const bundles = [
 
   /******* React DOM Fizz Server External Runtime *******/
   {
-    bundleTypes: [BROWSER_SCRIPT],
+    bundleTypes: __EXPERIMENTAL__ ? [BROWSER_SCRIPT] : [],
     moduleType: RENDERER,
     entry: 'react-dom/unstable_server-external-runtime',
     outputPath: 'unstable_server-external-runtime.js',
diff --git a/scripts/rollup/packaging.js b/scripts/rollup/packaging.js
index 0c7123fae6d13..b3b1a7cf9add1 100644
--- a/scripts/rollup/packaging.js
+++ b/scripts/rollup/packaging.js
@@ -235,7 +235,14 @@ function filterOutEntrypoints(name) {
       // Let's remove it.
       files.splice(i, 1);
       i--;
-      unlinkSync(`build/node_modules/${name}/${filename}`);
+      try {
+        unlinkSync(`build/node_modules/${name}/${filename}`);
+      } catch (err) {
+        // If the file doesn't exist we can just move on. Otherwise throw the halt the build
+        if (err.code !== 'ENOENT') {
+          throw err;
+        }
+      }
       changed = true;
       // Remove it from the exports field too if it exists.
       if (exportsJSON) {