diff --git a/reactos/lib/sdk/crt/stdio/file.c b/reactos/lib/sdk/crt/stdio/file.c
index 31502aa103e..f2b8dc2702b 100644
--- a/reactos/lib/sdk/crt/stdio/file.c
+++ b/reactos/lib/sdk/crt/stdio/file.c
@@ -1403,9 +1403,12 @@ char * CDECL _mktemp(char *pattern)
   int id;
   char letter = 'a';
 
+  if(!pattern)
+      return NULL;
+
   while(*pattern)
     numX = (*pattern++ == 'X')? numX + 1 : 0;
-  if (numX < 5)
+  if (numX < 6)
     return NULL;
   pattern--;
   id = GetCurrentProcessId();
@@ -1420,8 +1423,7 @@ char * CDECL _mktemp(char *pattern)
   do
   {
     *pattern = letter++;
-    if (GetFileAttributesA(retVal) == INVALID_FILE_ATTRIBUTES &&
-        GetLastError() == ERROR_FILE_NOT_FOUND)
+    if (GetFileAttributesA(retVal) == INVALID_FILE_ATTRIBUTES)
       return retVal;
   } while(letter <= 'z');
   return NULL;