diff --git a/drivers/filesystems/btrfs/fsctl.c b/drivers/filesystems/btrfs/fsctl.c
index 87556c47e15..6cc0f45ab18 100644
--- a/drivers/filesystems/btrfs/fsctl.c
+++ b/drivers/filesystems/btrfs/fsctl.c
@@ -5065,7 +5065,7 @@ NTSTATUS fsctl_request(PDEVICE_OBJECT DeviceObject, PIRP* Pirp, UINT32 type) {
             Status = STATUS_INVALID_DEVICE_REQUEST;
             break;
 
-#if WIN32_WINNT >= 0x0600
+#if _WIN32_WINNT >= 0x0600
         case FSCTL_MAKE_MEDIA_COMPATIBLE:
             WARN("STUB: FSCTL_MAKE_MEDIA_COMPATIBLE\n");
             Status = STATUS_INVALID_DEVICE_REQUEST;