From eab3e25cf211563b80faab9c3141c2d2b96b03cd Mon Sep 17 00:00:00 2001
From: Matt Nadareski <mnadareski@outlook.com>
Date: Thu, 31 Dec 2020 13:39:19 -0800
Subject: [PATCH] Fix crash on drive scan

---
 MPF/Windows/MainWindow.xaml.cs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/MPF/Windows/MainWindow.xaml.cs b/MPF/Windows/MainWindow.xaml.cs
index 5b5dccb1..3a256079 100644
--- a/MPF/Windows/MainWindow.xaml.cs
+++ b/MPF/Windows/MainWindow.xaml.cs
@@ -188,7 +188,7 @@ namespace MPF.Windows
         /// </summary>
         private void DetermineSystemType()
         {
-            if (!UIOptions.Options.SkipSystemDetection)
+            if (!UIOptions.Options.SkipSystemDetection && DriveLetterComboBox.SelectedIndex > -1)
             {
                 ViewModels.LoggerViewModel.VerboseLog("Trying to detect system for drive {0}.. ", Drives[DriveLetterComboBox.SelectedIndex].Letter);
                 var currentSystem = Validators.GetKnownSystem(Drives[DriveLetterComboBox.SelectedIndex]) ?? Converters.ToKnownSystem(UIOptions.Options.DefaultSystem);