diff --git a/weed/server/filer_server_handlers_read.go b/weed/server/filer_server_handlers_read.go
index 58d1928c6..99ac77498 100644
--- a/weed/server/filer_server_handlers_read.go
+++ b/weed/server/filer_server_handlers_read.go
@@ -162,6 +162,8 @@ func (fs *FilerServer) GetOrHeadHandler(w http.ResponseWriter, r *http.Request)
 	}
 	if mimeType != "" {
 		w.Header().Set("Content-Type", mimeType)
+	} else {
+		w.Header().Set("Content-Type", "application/octet-stream")
 	}
 
 	// print out the header from extended properties