diff --git a/src/python/classes/mainwindow.py b/src/python/classes/mainwindow.py
index 131c774..7f5ce07 100644
--- a/src/python/classes/mainwindow.py
+++ b/src/python/classes/mainwindow.py
@@ -46,10 +46,14 @@ class MainWindow(QMainWindow, Ui_MainWindow):
         dialog.setFileMode(QFileDialog.ExistingFile)
         file_formats = "All Files (*);;JPG (*.jpg);;PNG (*.png)"
         file, _ = dialog.getOpenFileName(self, "QFileDialog.getOpenFileName()", "", file_formats, options=dialog.options())
+        if not file:
+            msg = F"[!] Nie wybrano żadnego pliku."
+            dialog = self.create_custom_dialog(title='Ostrzeżenie', msg=msg)
+            dialog.exec_()
 
-        if not file.lower().endswith('.jpg') and not file.lower().endswith('.png'):
+        if file and not file.lower().endswith('.jpg') and not file.lower().endswith('.png'):
             msg = F"[!] Plik {file} nie jest plikiem jpg/png."
-            dialog = self.create_custom_dialog(title='Error', msg=msg)
+            dialog = self.create_custom_dialog(title='Błąd', msg=msg)
             dialog.exec_()
 
         else:
@@ -80,10 +84,14 @@ class MainWindow(QMainWindow, Ui_MainWindow):
         dialog.setFileMode(QFileDialog.ExistingFile)
         file_formats = "All Files (*);;mp3 (*.mp3);;wav (*.wav)"
         file, _ = dialog.getOpenFileName(self, "QFileDialog.getOpenFileName()", "", file_formats, options=dialog.options())
+        if not file:
+            msg = F"[!] Nie wybrano żadnego pliku."
+            dialog = self.create_custom_dialog(title='Ostrzeżenie', msg=msg)
+            dialog.exec_()
 
-        if not file.lower().endswith('.mp3') and not file.lower().endswith('.wav'):
+        elif not file.lower().endswith('.mp3') and not file.lower().endswith('.wav'):
             msg = F"[!] Plik {file} nie jest plikiem mp3/wav."
-            dialog = self.create_custom_dialog(title='Error', msg=msg)
+            dialog = self.create_custom_dialog(title='Błąd', msg=msg)
             dialog.exec_()
 
         else: