diff --git a/Source/Project64-core/N64System/N64DiskClass.cpp b/Source/Project64-core/N64System/N64DiskClass.cpp
index 813a559ec..cecc83c5c 100644
--- a/Source/Project64-core/N64System/N64DiskClass.cpp
+++ b/Source/Project64-core/N64System/N64DiskClass.cpp
@@ -290,7 +290,7 @@ void CN64Disk::ConvertDiskFormat()
         atrack = 0;
         for (track = 0; track < ZoneTracks[zone]; track++)
         {
-            if (track == SystemData[0x20 + zone * 0xC + atrack])
+            if (atrack < 0xC && track == SystemData[0x20 + zone * 0xC + atrack])
             {
                 memset((void *)(&BlockData0), 0, BLOCKSIZE(zone));
                 memset((void *)(&BlockData1), 0, BLOCKSIZE(zone));
@@ -327,7 +327,7 @@ void CN64Disk::ConvertDiskFormat()
         atrack = 0xB;
         for (track = 1; track < ZoneTracks[zone] + 1; track++)
         {
-            if ((ZoneTracks[zone] - track) == SystemData[0x20 + (zone)* 0xC + atrack])
+            if (atrack > -1 && (ZoneTracks[zone] - track) == SystemData[0x20 + (zone)* 0xC + atrack])
             {
                 memset((void *)(&BlockData0), 0, BLOCKSIZE(zone));
                 memset((void *)(&BlockData1), 0, BLOCKSIZE(zone));