diff --git a/reactos/ntoskrnl/ex/init.c b/reactos/ntoskrnl/ex/init.c
index 5b448efbbf1..c8fa84b6874 100644
--- a/reactos/ntoskrnl/ex/init.c
+++ b/reactos/ntoskrnl/ex/init.c
@@ -329,6 +329,7 @@ ExpInitNls(IN PLOADER_PARAMETER_BLOCK LoaderBlock)
     }
 
     /* Copy the codepage data in its new location. */
+    ASSERT(SectionBase > MmSystemRangeStart);
     RtlCopyMemory(SectionBase, ExpNlsTableBase, ExpNlsTableSize);
 
     /* Free the previously allocated buffer and set the new location */