diff --git a/PKHeX.Core/Saves/SAV4.cs b/PKHeX.Core/Saves/SAV4.cs
index 07510afed..9b56ea99c 100644
--- a/PKHeX.Core/Saves/SAV4.cs
+++ b/PKHeX.Core/Saves/SAV4.cs
@@ -579,7 +579,7 @@ public int Y
         // Storage
         public override int CurrentBox
         {
-            get => Data[Version == GameVersion.HGSS ? GetBoxOffset(BoxCount) : Box - 4];
+            get => (sbyte)Data[Version == GameVersion.HGSS ? GetBoxOffset(BoxCount) : Box - 4];
             set => Data[Version == GameVersion.HGSS ? GetBoxOffset(BoxCount) : Box - 4] = (byte)value;
         }
 
diff --git a/PKHeX.WinForms/Controls/SAV Editor/BoxEditor.cs b/PKHeX.WinForms/Controls/SAV Editor/BoxEditor.cs
index b57aecd65..35eb2a8fb 100644
--- a/PKHeX.WinForms/Controls/SAV Editor/BoxEditor.cs	
+++ b/PKHeX.WinForms/Controls/SAV Editor/BoxEditor.cs	
@@ -257,7 +257,10 @@ private void GetBox(object sender, EventArgs e)
         public void InitializeFromSAV(SaveFile sav)
         {
             Editor = new BoxEdit(sav);
-            Editor.LoadBox(sav.CurrentBox);
+            int box = sav.CurrentBox;
+            if ((uint)box >= sav.BoxCount)
+                box = 0;
+            Editor.LoadBox(box);
             ResetBoxNames();   // Display the Box Names
         }
     }