diff --git a/MdeModulePkg/Universal/Disk/PartitionDxe/Mbr.c b/MdeModulePkg/Universal/Disk/PartitionDxe/Mbr.c
index d71698c826..f89f3e190e 100644
--- a/MdeModulePkg/Universal/Disk/PartitionDxe/Mbr.c
+++ b/MdeModulePkg/Universal/Disk/PartitionDxe/Mbr.c
@@ -267,7 +267,7 @@ Returns:
         goto Done;
       }
 
-      if (Mbr->Partition[0].OSIndicator == 0) {
+      if (UNPACK_UINT32 (Mbr->Partition[0].SizeInLBA) == 0) {
         break;
       }