diff --git a/src/emqttd_ctl.erl b/src/emqttd_ctl.erl
index 048af3431..201641407 100644
--- a/src/emqttd_ctl.erl
+++ b/src/emqttd_ctl.erl
@@ -184,14 +184,14 @@ plugins(["list"]) ->
 
 plugins(["load", Name]) ->
     case emqttd_plugins:load(list_to_atom(Name)) of
-        {ok, StartedApps} -> ?PRINT("start apps: ~p, plugin ~s is loaded successfully.~n", [StartedApps, Name]);
-        {error, Reason} -> ?PRINT("load plugin error: ~s~n", [Reason])
+        {ok, StartedApps} -> ?PRINT("Start apps: ~p~nPlugin ~s loaded successfully.~n", [StartedApps, Name]);
+        {error, Reason} -> ?PRINT("load plugin error: ~p~n", [Reason])
     end;
 
 plugins(["unload", Name]) ->
     case emqttd_plugins:unload(list_to_atom(Name)) of
-        ok -> ?PRINT("plugin ~s is unloaded successfully.~n", [Name]);
-        {error, Reason} -> ?PRINT("unload plugin error: ~s~n", [Reason])
+        ok -> ?PRINT("Plugin ~s unloaded successfully.~n", [Name]);
+        {error, Reason} -> ?PRINT("unload plugin error: ~p~n", [Reason])
     end.
 
 trace(["list"]) ->
diff --git a/src/emqttd_plugins.erl b/src/emqttd_plugins.erl
index 9f3a9e2ef..b3ccc122d 100644
--- a/src/emqttd_plugins.erl
+++ b/src/emqttd_plugins.erl
@@ -157,6 +157,8 @@ load_app(App, Config) ->
     case application:load(App) of
         ok ->
             set_config(Config);
+        {error, {already_loaded, App}} ->
+            set_config(Config);
         {error, Error} ->
             {error, Error}
     end.
@@ -241,7 +243,7 @@ plugin_loaded(Name, true) ->
             case lists:member(Name, Names) of
                 false ->
                     %% write file if plugin is loaded
-                    write_loaded(lists:append(Names, Name));
+                    write_loaded(lists:append(Names, [Name]));
                 true ->
                     ignore
             end;
@@ -272,12 +274,14 @@ read_loaded(File) ->
     file:consult(File).
 
 write_loaded(AppNames) ->
-    case file:open(env(loaded_file), [binary, write]) of
+    {ok, File} = env(loaded_file),
+    case file:open(File, [binary, write]) of
         {ok, Fd} ->
             lists:foreach(fun(Name) ->
                 file:write(Fd, iolist_to_binary(io_lib:format("~s.~n", [Name])))
             end, AppNames);
         {error, Error} ->
+            lager:error("Open File ~p Error: ~p", [File, Error]),
             {error, Error}
     end.