diff --git a/apps/emqx_conf/src/emqx_conf.erl b/apps/emqx_conf/src/emqx_conf.erl
index f9e64ffa6..3a65efc53 100644
--- a/apps/emqx_conf/src/emqx_conf.erl
+++ b/apps/emqx_conf/src/emqx_conf.erl
@@ -219,7 +219,9 @@ resolve_schema_module() ->
         "emqx" ->
             emqx_conf_schema;
         "emqx-enterprise" ->
-            emqx_enterprise_schema
+            emqx_enterprise_schema;
+        false ->
+            error("PROFILE environment variable is not set")
     end.
 -else.
 -spec resolve_schema_module() -> no_return().