diff --git a/reactos/dll/ntdll/rtl/libsupp.c b/reactos/dll/ntdll/rtl/libsupp.c
index 90c3ce322fc..47e4359e054 100644
--- a/reactos/dll/ntdll/rtl/libsupp.c
+++ b/reactos/dll/ntdll/rtl/libsupp.c
@@ -18,6 +18,8 @@ PTEB LdrpTopLevelDllBeingLoadedTeb = NULL;
 
 /* FUNCTIONS ***************************************************************/
 
+#ifndef _M_AMD64
+// FIXME: Why "Not implemented"???
 /*
  * @implemented
  */
@@ -30,6 +32,7 @@ RtlWalkFrameChain(OUT PVOID *Callers,
     /* Not implemented for user-mode */
     return 0;
 }
+#endif
 
 BOOLEAN
 NTAPI