diff --git a/src/os_win32.c b/src/os_win32.c
index e9ec5f7..844b70a 100644
--- a/src/os_win32.c
+++ b/src/os_win32.c
@@ -4627,6 +4627,7 @@
 	    DWORD		flags = CREATE_NEW_CONSOLE;
 	    char_u		*p;
 
+	    ZeroMemory(&si, sizeof(si));
 	    si.cb = sizeof(si);
 	    si.lpReserved = NULL;
 	    si.lpDesktop = NULL;
@@ -4723,9 +4724,9 @@
 	    if (newcmd != cmdbase)
 		vim_free(newcmd);
 
-	    if (si.hStdInput != NULL)
+	    if (si.dwFlags == STARTF_USESTDHANDLES && si.hStdInput != NULL)
 	    {
-		/* Close the handle to \\.\NUL */
+		/* Close the handle to \\.\NUL created above. */
 		CloseHandle(si.hStdInput);
 	    }
 	    /* Close the handles to the subprocess, so that it goes away */