diff --git a/packages/core/admin/_internal/node/core/admin-customisations.ts b/packages/core/admin/_internal/node/core/admin-customisations.ts
index 6e8612c6b1d..e6dabbdac0c 100644
--- a/packages/core/admin/_internal/node/core/admin-customisations.ts
+++ b/packages/core/admin/_internal/node/core/admin-customisations.ts
@@ -1,5 +1,5 @@
 import path from 'node:path';
-import { loadFile } from './files';
+import fs from 'node:fs';
 
 const ADMIN_APP_FILES = ['app.js', 'app.mjs', 'app.ts', 'app.jsx', 'app.tsx'];
 
@@ -12,16 +12,14 @@ interface AdminCustomisations {
 
 interface AppFile {
   path: string;
-  config: AdminCustomisations['config'];
 }
 
 const loadUserAppFile = async (appDir: string): Promise<AppFile | undefined> => {
   for (const file of ADMIN_APP_FILES) {
     const filePath = path.join(appDir, 'src', 'admin', file);
-    const configFile = await loadFile(filePath);
 
-    if (configFile) {
-      return { path: filePath, config: configFile };
+    if (fs.existsSync(filePath)) {
+      return { path: filePath };
     }
   }
 
diff --git a/packages/core/admin/_internal/node/core/files.ts b/packages/core/admin/_internal/node/core/files.ts
index f9fd9a52b01..3771a1f5bc2 100644
--- a/packages/core/admin/_internal/node/core/files.ts
+++ b/packages/core/admin/_internal/node/core/files.ts
@@ -19,9 +19,7 @@ const pathExists = async (path: string) => {
 const loadFile = async (path: string): Promise<undefined | any> => {
   if (await pathExists(path)) {
     const esbuildOptions: Parameters<typeof register>[0] = {
-      extensions: ['.js', '.mjs', '.ts', '.jsx', '.tsx'],
-      jsx: 'automatic',
-      loader: 'jsx',
+      extensions: ['.js', '.mjs', '.ts'],
     };
 
     const { unregister } = register(esbuildOptions);