diff --git a/targets.hpp b/targets.hpp
index 7f21c4b..cb25dee 100644
--- a/targets.hpp
+++ b/targets.hpp
@@ -129,7 +129,7 @@
                 using namespace phosphor::logging;
                 log<level::ERR>("Invalid TARGET_MODE env var found",
                         phosphor::logging::entry(
-                                "TARGET_MODE=%s", tmEnv),
+                                "TARGET_MODE=%s", tmEnv.c_str()),
                         phosphor::logging::entry(
                                 "DEVPATH=%s", devPath.c_str()));
             }