diff --git a/pyproject.toml b/pyproject.toml
index b885c57..f44fd33 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -5,7 +5,7 @@ dependencies = [
     "comtypes; platform_system == 'Windows'",
     "pypiwin32; platform_system == 'Windows'",
     "pywin32; platform_system == 'Windows'",
-    "pyobjc>=2.4; platform_system == 'Darwin'",
+    "pyobjc==9.0.1; platform_system == 'Darwin'",
     "six"
 ]
 description = "Text to Speech (TTS) library for Python 3. Works without internet connection or delay. Supports multiple TTS engines, including Sapi5, nsss, and espeak."
diff --git a/pyttsx3/__init__.py b/pyttsx3/__init__.py
index 3b05b89..9eb0e31 100644
--- a/pyttsx3/__init__.py
+++ b/pyttsx3/__init__.py
@@ -2,7 +2,7 @@
 
 from .engine import Engine
 
-version = '3.4.0'
+version = '3.5'
 _activeEngines = weakref.WeakValueDictionary()
 
 
diff --git a/pyttsx3/drivers/nsss.py b/pyttsx3/drivers/nsss.py
index 08a78f6..6243fd7 100644
--- a/pyttsx3/drivers/nsss.py
+++ b/pyttsx3/drivers/nsss.py
@@ -1,5 +1,3 @@
-import time
-
 # noinspection PyUnresolvedReferences
 from AppKit import NSSpeechSynthesizer
 from Foundation import *
@@ -141,10 +139,10 @@ def setProperty(self, name, value):
 
     @objc.python_method
     def save_to_file(self, text, filename):
+        self._proxy.setBusy(True)
+        self._completed = True
         url = Foundation.NSURL.fileURLWithPath_(filename)
         self._tts.startSpeakingString_toURL_(text, url)
-        # waits (for 1% of the length of text) the system to finish writing to the file system before continuing
-        time.sleep(max(1.0, len(text) * 0.01))
 
     def speechSynthesizer_didFinishSpeaking_(self, tts, success):
         if not self._completed: