diff --git a/PKHeX.Core/Saves/SAV3.cs b/PKHeX.Core/Saves/SAV3.cs
index 4f8a5d2b9..86b796640 100644
--- a/PKHeX.Core/Saves/SAV3.cs
+++ b/PKHeX.Core/Saves/SAV3.cs
@@ -97,7 +97,7 @@ public static bool IsAllMainSectorsPresent(byte[] data, int slot, out int sector
             int end = start + SIZE_MAIN;
             int bitTrack = 0;
             sector0 = 0;
-            for (int ofs = 0; ofs < end; ofs += SIZE_SECTOR)
+            for (int ofs = start; ofs < end; ofs += SIZE_SECTOR)
             {
                 var id = BitConverter.ToInt16(data, ofs + 0xFF4);
                 bitTrack |= (1 << id);