diff --git a/src/onedrive_gui/OneDriveGUI.py b/src/onedrive_gui/OneDriveGUI.py
index 68b9b7f..d69eb1a 100644
--- a/src/onedrive_gui/OneDriveGUI.py
+++ b/src/onedrive_gui/OneDriveGUI.py
@@ -20,6 +20,10 @@ app = QApplication(sys.argv)
 app.setApplicationName("OneDriveGUI")
 app.setDesktopFileName("OneDriveGUI")
 app.setWindowIcon(QIcon(DIR_PATH + "/resources/images/icons8-cloud-80.png"))
+# OneDriveGUI lives in the system tray: closing a dialog while the main window is
+# hidden (e.g. the resync prompt with start_minimized) must not quit the app and
+# destroy the still-running worker threads (#297). Quitting is explicit.
+app.setQuitOnLastWindowClosed(False)
 
 
 from .options import gui_settings, global_config, version
diff --git a/src/onedrive_gui/main_window.py b/src/onedrive_gui/main_window.py
index 9bbfe1c..64e12c0 100644
--- a/src/onedrive_gui/main_window.py
+++ b/src/onedrive_gui/main_window.py
@@ -206,6 +206,10 @@ class MainWindow(QMainWindow, Ui_MainWindow):
             "tooltip_text": "",
         }
 
+        # Stop the clients and their worker threads before the application is torn
+        # down; destroying a QThread that is still running aborts the process.
+        QApplication.instance().aboutToQuit.connect(self.stop_all_workers)
+
         self.refresh_process_status = QTimer()
         self.refresh_process_status.setSingleShot(False)
         self.refresh_process_status.timeout.connect(self.onedrive_process_status)
@@ -288,19 +292,16 @@ class MainWindow(QMainWindow, Ui_MainWindow):
 
         if close_question == QMessageBox.Yes:
             logging.info("Quitting OneDriveGUI")
-            workers_to_stop = []
-
-            for worker in workers:
-                workers_to_stop.append(worker)
-
-            for worker in workers_to_stop:
-                workers[worker].stop_worker()
-
-            sys.exit()
+            self.stop_all_workers()
+            QApplication.instance().quit()
 
         elif close_question == QMessageBox.No:
             logging.info("[GUI] Keeping OneDriveGUI running.")
 
+    def stop_all_workers(self):
+        for profile_name in list(workers):
+            workers[profile_name].stop_worker()
+
     def stop_onedrive_monitor(self, profile_name):
         if profile_name in workers:
             workers[profile_name].stop_worker()