diff --git a/sane/scanner.cpp b/sane/scanner.cpp
index 2cccef5..68ed065 100644
--- a/sane/scanner.cpp
+++ b/sane/scanner.cpp
@@ -85,7 +85,13 @@ namespace callback
 		if (it != g_scanner_instances.end())
 			return it->invoker->handle_device_event(code, data, len);
 		else
+		{
+			wchar_t	msg[218] = { 0 };
+			swprintf_s(msg, _countof(msg) - 1, L"Lost device(0x%08X) when event(%u) occurs!\r\n", hdev, code);
+			log_info(msg, 0);
+
 			return 0;
+		}
 	}
 	void reg_callback(SANE_Handle dev, scanner* invoker)
 	{
@@ -132,7 +138,6 @@ scanner::scanner(SCANNERID id) : handle_(NULL), id_(id), ex_id_(EXTENSION_ID_BAS
 }
 scanner::~scanner()
 {
-	callback::unreg_callback(this);
 	if (cfg_)
 		delete cfg_;
 }
@@ -282,8 +287,8 @@ int scanner::open(void)
 	ret = hg_sane_middleware::instance()->open_device(name.c_str(), &handle_);
 	if (ret == SANE_STATUS_GOOD)
 	{
-		scanner_name_ = local_trans::a2u(name.c_str(), CP_UTF8);
 		callback::reg_callback(handle_, this);
+		scanner_name_ = local_trans::a2u(name.c_str(), CP_UTF8);
 		ret = init_options_id();
 		load_config((cfg_path_ + scanner_name_).c_str());
 		// apply_config();
@@ -293,6 +298,7 @@ int scanner::open(void)
 }
 int scanner::close(void)
 {
+	callback::unreg_callback(this);
 	if (handle_)
 		hg_sane_middleware::instance()->close_device(handle_);
 	handle_ = NULL;