diff --git a/packages/mui-system/src/cssVars/createCssVarsProvider.js b/packages/mui-system/src/cssVars/createCssVarsProvider.js
index ddd9398f91ce53..cb0670ed1d8e28 100644
--- a/packages/mui-system/src/cssVars/createCssVarsProvider.js
+++ b/packages/mui-system/src/cssVars/createCssVarsProvider.js
@@ -1,3 +1,4 @@
+'use client';
 import * as React from 'react';
 import PropTypes from 'prop-types';
 import MuiError from '@mui/utils/macros/MuiError.macro';
diff --git a/packages/mui-system/src/cssVars/getInitColorSchemeScript.tsx b/packages/mui-system/src/cssVars/getInitColorSchemeScript.tsx
index d392ddbc8d053d..416092ade33968 100644
--- a/packages/mui-system/src/cssVars/getInitColorSchemeScript.tsx
+++ b/packages/mui-system/src/cssVars/getInitColorSchemeScript.tsx
@@ -1,3 +1,4 @@
+'use client';
 import * as React from 'react';
 
 export const DEFAULT_MODE_STORAGE_KEY = 'mode';
diff --git a/packages/rsc-builder/buildRsc.ts b/packages/rsc-builder/buildRsc.ts
index 3a4616d63a967f..59705255ed8dcd 100644
--- a/packages/rsc-builder/buildRsc.ts
+++ b/packages/rsc-builder/buildRsc.ts
@@ -73,21 +73,6 @@ async function processFile(
   await fse.writeFile(filename, newContents);
 }
 
-function getIndexFile(directory: string) {
-  const items = fse.readdirSync(directory);
-
-  const indexFile = items.reduce((prev, curr) => {
-    if (!/^index.(js|ts)/.test(curr)) {
-      return prev;
-    }
-    return curr;
-  }, '');
-
-  return {
-    filename: path.join(directory, indexFile),
-  };
-}
-
 async function findAll(
   directories: string[],
   grep: RegExp | null,
@@ -124,24 +109,11 @@ async function run(argv: yargs.ArgumentsCamelCase<CommandOptions>) {
       ];
     }
 
-    const indexFile = getIndexFile(projectSrc);
-
-    try {
-      processFile(indexFile.filename);
-    } catch (error: any) {
-      error.message = `${path.relative(process.cwd(), indexFile.filename)}: ${error.message}`;
-      throw error;
-    }
-
     const components = await findAll(directories, grep, findComponents);
 
     components.forEach(async (component) => {
       try {
         processFile(component.filename);
-
-        if (component.indexFilename) {
-          processFile(component.indexFilename);
-        }
       } catch (error: any) {
         error.message = `${path.relative(process.cwd(), component.filename)}: ${error.message}`;
         throw error;
@@ -153,10 +125,6 @@ async function run(argv: yargs.ArgumentsCamelCase<CommandOptions>) {
     hooks.forEach(async (hook) => {
       try {
         processFile(hook.filename);
-
-        if (hook.indexFilename) {
-          processFile(hook.indexFilename);
-        }
       } catch (error: any) {
         error.message = `${path.relative(process.cwd(), hook.filename)}: ${error.message}`;
         throw error;