diff --git a/fftools/ffprobe.c b/fftools/ffprobe.c
index f5c83925b9..d980d4e64f 100644
--- a/fftools/ffprobe.c
+++ b/fftools/ffprobe.c
@@ -3081,6 +3081,8 @@ int main(int argc, char **argv)
 
     init_dynload();
 
+    setvbuf(stderr, NULL, _IONBF, 0); /* win32 runtime needs this */
+
     av_log_set_flags(AV_LOG_SKIP_REPEATED);
 
     options = real_options;