diff --git a/UnityLauncherPro/UpgradeWindow.xaml.cs b/UnityLauncherPro/UpgradeWindow.xaml.cs
index 5e5944e..12d5b32 100644
--- a/UnityLauncherPro/UpgradeWindow.xaml.cs
+++ b/UnityLauncherPro/UpgradeWindow.xaml.cs
@@ -21,7 +21,14 @@ public UpgradeWindow(string currentVersion, string projectPath, string commandLi
 
             if (gridAvailableVersions.ItemsSource == null)
             {
-                gridAvailableVersions.ItemsSource = MainWindow.unityInstallationsSource;
+                if (MainWindow.unityInstallationsSource != null)
+                {
+                    gridAvailableVersions.ItemsSource = MainWindow.unityInstallationsSource;
+                }
+                else
+                {
+                    gridAvailableVersions.ItemsSource = new System.Collections.Generic.List<UnityInstallation>();
+                }
             }
 
             gridAvailableVersions.SelectedItem = null;