diff --git a/msg.go b/msg.go
index 7be9ede..34c209d 100644
--- a/msg.go
+++ b/msg.go
@@ -327,6 +327,10 @@ func UnzipMessages(z []byte) error {
 	log.Printf("UnzipMessages : %d bytes.\n", len(z))
 	r := bytes.NewReader(z)
 	zr, err := zip.NewReader(r, int64(len(z)))
+	logOnError("UnzipMessages : NewReader")
+	if err != nil {
+		return err
+	}
 
 	for _, f := range zr.File {
 		log.Printf("File : %s\n", f.Name)