diff --git a/app.py b/app.py
index bb68402..f204d13 100644
--- a/app.py
+++ b/app.py
@@ -42,16 +42,20 @@ app.permanent_session_lifetime = timedelta(days=30)
 def cargar_usuarios():
     if not USERS_FILE.exists():
         return {}
-    with open(USERS_FILE, encoding="utf-8") as f:
-        return json.load(f)
+    try:
+        with open(USERS_FILE, encoding="utf-8") as f:
+            contenido = f.read().strip()
+            return json.loads(contenido) if contenido else {}
+    except json.JSONDecodeError:
+        return {}
 
 def guardar_usuarios(users):
     with open(USERS_FILE, "w", encoding="utf-8") as f:
         json.dump(users, f, indent=2, ensure_ascii=False)
 
 def inicializar_admin():
-    """Crea el usuario admin la primera vez si no existe users.json."""
-    if USERS_FILE.exists():
+    """Crea el usuario admin la primera vez si users.json no existe o está vacío."""
+    if USERS_FILE.exists() and USERS_FILE.stat().st_size > 0:
         return
     pwd = os.environ.get("ADMIN_PASSWORD", "cambia-esta-password")
     users = {