diff --git a/src/net/sendfile_windows.go b/src/net/sendfile_windows.go
index b128ba2..f3f3b54 100644
--- a/src/net/sendfile_windows.go
+++ b/src/net/sendfile_windows.go
@@ -46,7 +46,7 @@
 		return syscall.TransmitFile(o.fd.sysfd, o.handle, o.qty, 0, &o.o, nil, syscall.TF_WRITE_BEHIND)
 	})
 	if err != nil {
-		return 0, err, false
+		return 0, os.NewSyscallError("transmitfile", err), false
 	}
 	if lr != nil {
 		lr.N -= int64(done)