diff --git a/src/LipUI/Global.cs b/src/LipUI/Global.cs
index b2f20b2..3cccf4e 100644
--- a/src/LipUI/Global.cs
+++ b/src/LipUI/Global.cs
@@ -379,7 +379,7 @@ void Save()
                     {
                         Directory.CreateDirectory(dir);
                     }
-                    File.WriteAllText(fp, result.ToString());
+                    File.WriteAllText(fp, result?.ToString());
                 }
                 catch
                 {
diff --git a/src/LipUI/ViewModels/InstallPageViewModel.cs b/src/LipUI/ViewModels/InstallPageViewModel.cs
index a0d6471..ead3f38 100644
--- a/src/LipUI/ViewModels/InstallPageViewModel.cs
+++ b/src/LipUI/ViewModels/InstallPageViewModel.cs
@@ -193,7 +193,7 @@ public async Task FetchInfo()
                 });
                 if (success)
                 {
-                    if (ToothInfoPanel.Tooth != ToothName)
+                    if (ToothInfoPanel?.Tooth != ToothName)
                     {
                         ToothInfoPanel = new ToothInfoPanelViewModel(package!)
                         {