diff --git a/dlls/ntdll/nt.c b/dlls/ntdll/nt.c
index e70bf270a59..93da87e59ae 100644
--- a/dlls/ntdll/nt.c
+++ b/dlls/ntdll/nt.c
@@ -520,9 +520,12 @@ NTSTATUS WINAPI NtQueryPerformanceCounter(
 	OUT PLARGE_INTEGER Frequency)
 {
     LARGE_INTEGER time;
+
+    if (!Counter) return STATUS_ACCESS_VIOLATION;
     NtQuerySystemTime( &time );
     Counter->QuadPart = time.QuadPart;
-    Frequency->QuadPart = 10000000;
+    if (Frequency)
+        Frequency->QuadPart = 10000000;
     return 0;
 }