diff --git a/libgrive/src/drive/Drive.cc b/libgrive/src/drive/Drive.cc
index bcf0af2..9760972 100644
--- a/libgrive/src/drive/Drive.cc
+++ b/libgrive/src/drive/Drive.cc
@@ -23,7 +23,7 @@
 #include "Entry.hh"
 
 #include "http/Agent.hh"
-#include "http/ResponseLog.hh"
+// #include "http/ResponseLog.hh"
 #include "http/XmlResponse.hh"
 #include "protocol/Json.hh"
 #include "protocol/OAuth2.hh"
@@ -97,7 +97,6 @@ Drive::Drive( OAuth2& auth ) :
 			if ( file.Kind() != "folder" )
 			{
 				Resource *p = m_state.FindFolderByHref( file.ParentHref() ) ;
-Trace( "finding parent of %1%: %2%", file.Title(), (void*)p ) ;
 				if ( file.Filename().empty() )
 					Log( "file \"%1%\" is a google document, ignored", file.Title() ) ;
 				
@@ -118,8 +117,8 @@ Trace( "finding parent of %1%: %2%", file.Title(), (void*)p ) ;
 
 		if ( has_next )
 		{
-			http::ResponseLog log2( "second-", ".xml", &xrsp ) ;
-			http.Get( nss["@href"], &log2, m_http_hdr ) ;
+// 			http::ResponseLog log2( "second-", ".xml", &xrsp ) ;
+			http.Get( nss["@href"], &xrsp, m_http_hdr ) ;
 			resp = xrsp.Response() ;
 		}
 	} while ( has_next ) ;
@@ -133,9 +132,9 @@ void Drive::SaveState()
 void Drive::ConstructDirTree( http::Agent *http )
 {
 	http::XmlResponse xml ;
-	http::ResponseLog log( "dir-", ".xml", &xml ) ;
+// 	http::ResponseLog log( "dir-", ".xml", &xml ) ;
 	
-	http->Get( feed_base + "/-/folder?max-results=10&showroot=true", &log, m_http_hdr ) ;
+	http->Get( feed_base + "/-/folder?max-results=10&showroot=true", &xml, m_http_hdr ) ;
 
 	xml::Node resp = xml.Response() ;
 
diff --git a/libgrive/src/drive/Resource.cc b/libgrive/src/drive/Resource.cc
index d24e8d0..f1b2994 100644
--- a/libgrive/src/drive/Resource.cc
+++ b/libgrive/src/drive/Resource.cc
@@ -45,7 +45,10 @@ Resource::Resource() :
 {
 }
 
-/// construct from previously serialized JSON object
+/// Construct from previously serialized JSON object. The state of the
+/// resource is treated as local_deleted by default. It is because the
+/// state will be updated by scanning the local directory. If the state
+/// is not updated during scanning, that means the resource is deleted.
 Resource::Resource( const Json& json, Resource *parent ) :
 	m_entry	(
 		json["name"].Str(),
@@ -56,8 +59,11 @@ Resource::Resource( const Json& json, Resource *parent ) :
 		DateTime( json["mtime"]["sec"].Int(), json["mtime"]["nsec"].Int() ),
 		parent != 0 ? parent->SelfHref() : "" ),
 	m_parent( parent ),
-	m_state( local_new )
+	m_state( local_deleted )
 {
+	// if the file exists in local directory, FromLocal() will mark the
+	// state as local_changed
+	FromLocal() ;
 }
 
 Resource::Resource( const xml::Node& entry ) :
@@ -79,7 +85,6 @@ Resource::Resource( const fs::path& path ) :
 	m_parent( 0 ),
 	m_state	( local_new )
 {
-	
 }
 
 /// Update the state according to information (i.e. Entry) from remote. This function
@@ -94,12 +99,32 @@ void Resource::FromRemote( const Entry& remote )
 	// use mtime to check which one is more recent
 	else
 	{
-		m_state = ( remote.MTime() > m_entry.MTime() ? remote_changed : local_changed ) ;
+		assert( m_state == local_new || m_state == local_changed || m_state == local_deleted ) ;
+		
+		m_state = ( remote.MTime() > m_entry.MTime() ? remote_changed : m_state ) ;
 	}
 	
 	m_entry = remote ;
 }
 
+void Resource::FromLocal()
+{
+	fs::path path = Path() ;
+	if ( !fs::exists( path ) )
+		m_state = local_deleted ;
+	
+	// to save time, compare mtime before checksum
+	else if ( m_entry.MTime() > os::FileMTime( path ) )
+	{
+		if ( m_entry.MD5() == crypt::MD5( path ) )
+			m_state = local_new ;
+		else
+			m_state = local_changed ;
+	}
+	else
+		m_state = local_changed ;
+}
+
 std::string Resource::SelfHref() const
 {
 	return m_entry.SelfHref() ;
diff --git a/libgrive/src/drive/Resource.hh b/libgrive/src/drive/Resource.hh
index b271018..ca8de94 100644
--- a/libgrive/src/drive/Resource.hh
+++ b/libgrive/src/drive/Resource.hh
@@ -71,6 +71,8 @@ public :
 	bool IsInRootTree() const ;
 
 	void FromRemote( const Entry& e ) ;
+	void FromLocal() ;
+	
 	void Sync( http::Agent *http, const http::Headers& auth ) ;
 	void Delete( http::Agent* http, const http::Headers& auth ) ;
 
@@ -96,6 +98,9 @@ private :
 		/// than remote. We should upload local copy to overwrite remote.
 		local_changed,
 		
+		/// Resource deleted from local since last time grive has checked.
+		local_deleted,
+		
 		/// Resource created in google drive, but not exist in local.
 		/// We should download the file.
 		remote_new,
diff --git a/libgrive/src/drive/State.cc b/libgrive/src/drive/State.cc
index 99582ae..c114c0a 100644
--- a/libgrive/src/drive/State.cc
+++ b/libgrive/src/drive/State.cc
@@ -75,11 +75,7 @@ void State::FromLocal( const fs::path& p, gr::Resource* folder )
 		else
 		{
 			Resource *c = folder->FindChild( fname ) ;
-			if ( c != 0 )
-			{
-				Trace( "wow! file %1% is loaded from previous state", fname ) ;
-			}
-			else
+			if ( c == 0 )
 			{
 				c = new Resource( i->path() ) ;
 				folder->AddChild( c ) ;
@@ -133,14 +129,12 @@ bool State::Update( const Entry& e )
 {
 	assert( !e.ParentHref().empty() ) ;
 	
-	Resource *r = m_res.FindByHref( e.SelfHref() ) ;
-	if ( r != 0 )
+	if ( Resource *res = m_res.FindByHref( e.SelfHref() ) )
 	{
-Trace( "wow! find %1% from state file?", r->Name() ) ;
+		m_res.Update( res, e ) ;
+		return true ;
 	}
-	
-	Resource *parent = m_res.FindByHref( e.ParentHref() ) ;
-	if ( parent != 0 )
+	else if ( Resource *parent = m_res.FindByHref( e.ParentHref() ) )
 	{
 		assert( parent->IsFolder() ) ;