diff --git a/bypy/windows/util.c b/bypy/windows/util.c
index 65d258d34d..d9a5c5f415 100644
--- a/bypy/windows/util.c
+++ b/bypy/windows/util.c
@@ -116,7 +116,9 @@ setup_streams() {
 }
 
 
-void redirect_out_stream(FILE *stream) {
+void
+redirect_out_stream(FILE *stream) {
+    if (_isatty(_fileno(stream))) return;
     FILE *f = NULL;
     errno_t err;