diff --git a/sal/osl/w32/random.c b/sal/osl/w32/random.c
index 78ea5bfae27f..d394f19a03af 100644
--- a/sal/osl/w32/random.c
+++ b/sal/osl/w32/random.c
@@ -6,7 +6,10 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
+
+#if !defined _CRT_RAND_S
 #define _CRT_RAND_S
+#endif
 
 #include <stdlib.h>
 #include <memory.h>