diff --git a/dlls/ntdll/string.c b/dlls/ntdll/string.c
index 731d918e878..92aa808c70d 100644
--- a/dlls/ntdll/string.c
+++ b/dlls/ntdll/string.c
@@ -106,9 +106,10 @@ void __cdecl NTDLL_qsort( void *base, size_t nmemb, size_t size,
  *                  _lfind   (NTDLL.@)
  */
 void * __cdecl _lfind( const void *key, const void *base, unsigned int *nmemb,
-                       unsigned int size, int(*compar)(const void *, const void *) )
+                       size_t size, int(*compar)(const void *, const void *) )
 {
-    return lfind( key, base, nmemb, size, compar );
+    size_t n = *nmemb;
+    return lfind( key, base, &n, size, compar );
 }