diff --git a/lib/Support/Errno.cpp b/lib/Support/Errno.cpp
index 00be43b7503..730220f47d9 100644
--- a/lib/Support/Errno.cpp
+++ b/lib/Support/Errno.cpp
@@ -53,8 +53,10 @@ std::string StrError(int errnum) {
     str = buffer;
 # endif
 #elif HAVE_DECL_STRERROR_S // "Windows Secure API"
-    if (errnum)
+    if (errnum) {
       strerror_s(buffer, MaxErrStrLen - 1, errnum);
+      str = buffer;
+    }
 #elif defined(HAVE_STRERROR)
   // Copy the thread un-safe result of strerror into
   // the buffer as fast as possible to minimize impact