diff --git a/reactos/ntoskrnl/se/sd.c b/reactos/ntoskrnl/se/sd.c
index d3079dc3284..d6e5b53bb66 100644
--- a/reactos/ntoskrnl/se/sd.c
+++ b/reactos/ntoskrnl/se/sd.c
@@ -986,7 +986,7 @@ SeValidSecurityDescriptor(IN ULONG Length,
     SdLength = sizeof(SECURITY_DESCRIPTOR);
 
     /* Check Owner SID */
-    if (SecurityDescriptor->Owner)
+    if (!SecurityDescriptor->Owner)
     {
         DPRINT1("No Owner SID\n");
         return FALSE;