diff --git a/dlcservice_chromeos.cc b/dlcservice_chromeos.cc
index b7dee36..ad5806a 100644
--- a/dlcservice_chromeos.cc
+++ b/dlcservice_chromeos.cc
@@ -35,6 +35,8 @@
 bool DlcServiceChromeOS::GetInstalled(vector<string>* dlc_module_ids) {
   if (!dlc_module_ids)
     return false;
+  dlc_module_ids->clear();
+
   org::chromium::DlcServiceInterfaceProxy dlcservice_proxy(
       DBusConnection::Get()->GetDBus());