diff --git a/README.md b/README.md
index 756873b..2b0f69e 100644
--- a/README.md
+++ b/README.md
@@ -75,6 +75,7 @@ Enjoy!
 - Much faster and more correct synchronisation using local modification time and checksum cache (similar to git index)
 - Automatic move/rename detection, -m option removed
 - force option works again
+- Instead of crashing on sync exceptions Grive will give a warning and attempt to sync failed files again during the next run.
 
 ### Grive2 v0.4.2
 
diff --git a/libgrive/src/base/Drive.cc b/libgrive/src/base/Drive.cc
index 9dd8089..5e3eaaf 100644
--- a/libgrive/src/base/Drive.cc
+++ b/libgrive/src/base/Drive.cc
@@ -35,7 +35,6 @@
 #include <cstdlib>
 #include <fstream>
 #include <map>
-#include <sstream>
 
 // for debugging only
 #include <iostream>
diff --git a/libgrive/src/base/Resource.cc b/libgrive/src/base/Resource.cc
index 66a4ac3..a0d571b 100644
--- a/libgrive/src/base/Resource.cc
+++ b/libgrive/src/base/Resource.cc
@@ -28,6 +28,7 @@
 #include "util/log/Log.hh"
 #include "util/OS.hh"
 #include "util/File.hh"
+#include "http/Error.hh"
 
 #include <boost/exception/all.hpp>
 #include <boost/filesystem.hpp>
@@ -264,18 +265,12 @@ void Resource::FromLocal( Val& state )
 				m_md5 = crypt::MD5::Get( path );
 				// File is changed locally. TODO: Detect conflicts
 				is_changed = !state.Has( "md5" ) || m_md5 != state["md5"].Str();
-				state.Set( "md5", Val( m_md5 ) );
 			}
 			else
 				is_changed = true;
-			state.Set( "ctime", Val( m_ctime.Sec() ) );
 		}
 		if ( state.Has( "srv_time" ) )
 			m_mtime.Assign( state[ "srv_time" ].U64(), 0 ) ;
-		if ( is_dir )
-			state.Del( "md5" );
-		else
-			state.Del( "tree" );
 
 		// follow parent recursively
 		if ( m_parent->m_state == local_new || m_parent->m_state == remote_deleted )
@@ -418,6 +413,32 @@ void Resource::Sync( Syncer *syncer, ResourceTree *res_tree, const Val& options
 		Log( "Error syncing %1%: %2%", Path(), e.what(), log::error );
 		return;
 	}
+	catch ( http::Error &e )
+	{
+		int *curlcode = boost::get_error_info< http::CurlCode > ( e ) ;
+		int *httpcode = boost::get_error_info< http::HttpResponseCode > ( e ) ;
+		std::string msg;
+		if ( curlcode )
+			msg = *( boost::get_error_info< http::CurlErrMsg > ( e ) );
+		else if ( httpcode )
+			msg = "HTTP " + boost::to_string( *httpcode );
+		else
+			msg = e.what();
+		Log( "Error syncing %1%: %2%", Path(), msg, log::error );
+		std::string *url = boost::get_error_info< http::Url > ( e );
+		std::string *resp_hdr = boost::get_error_info< http::HttpResponseHeaders > ( e );
+		std::string *resp_txt = boost::get_error_info< http::HttpResponseText > ( e );
+		http::Header *req_hdr = boost::get_error_info< http::HttpRequestHeaders > ( e );
+		if ( url )
+			Log( "Request URL: %1%", *url, log::verbose );
+		if ( req_hdr )
+			Log( "Request headers: %1%", req_hdr->Str(), log::verbose );
+		if ( resp_hdr )
+			Log( "Response headers: %1%", *resp_hdr, log::verbose );
+		if ( resp_txt )
+			Log( "Response text: %1%", *resp_txt, log::verbose );
+		return;
+	}
 	
 	// if myself is deleted, no need to do the childrens
 	if ( m_state != local_deleted && m_state != remote_deleted )
@@ -463,11 +484,14 @@ void Resource::SyncSelf( Syncer* syncer, ResourceTree *res_tree, const Val& opti
 				if ( syncer )
 				{
 					if ( is_local )
+					{
 						syncer->Move( from, to->Parent(), to->Name() );
+						to->SetIndex( false );
+					}
 					else
 					{
 						fs::rename( from->Path(), to->Path() );
-						to->SetIndex();
+						to->SetIndex( true );
 					}
 					to->m_mtime = from->m_mtime;
 					to->m_json->Set( "srv_time", Val( from->m_mtime.Sec() ) );
@@ -485,9 +509,11 @@ void Resource::SyncSelf( Syncer* syncer, ResourceTree *res_tree, const Val& opti
 	case local_new :
 		Log( "sync %1% doesn't exist in server, uploading", path, log::info ) ;
 		
-		// FIXME: (?) do not write new timestamp on failed upload
 		if ( syncer && syncer->Create( this ) )
+		{
 			m_state = sync ;
+			SetIndex( false );
+		}
 		break ;
 	
 	case local_deleted :
@@ -502,7 +528,10 @@ void Resource::SyncSelf( Syncer* syncer, ResourceTree *res_tree, const Val& opti
 	case local_changed :
 		Log( "sync %1% changed in local. uploading", path, log::info ) ;
 		if ( syncer && syncer->EditContent( this, options["new-rev"].Bool() ) )
+		{
 			m_state = sync ;
+			SetIndex( false );
+		}
 		break ;
 	
 	case remote_new :
@@ -513,7 +542,7 @@ void Resource::SyncSelf( Syncer* syncer, ResourceTree *res_tree, const Val& opti
 				fs::create_directories( path ) ;
 			else
 				syncer->Download( this, path ) ;
-			SetIndex() ;
+			SetIndex( true ) ;
 			m_state = sync ;
 		}
 		break ;
@@ -524,7 +553,7 @@ void Resource::SyncSelf( Syncer* syncer, ResourceTree *res_tree, const Val& opti
 		if ( syncer )
 		{
 			syncer->Download( this, path ) ;
-			SetIndex() ;
+			SetIndex( true ) ;
 			m_state = sync ;
 		}
 		break ;
@@ -604,21 +633,26 @@ void Resource::DeleteIndex()
 	m_json = NULL;
 }
 
-void Resource::SetIndex()
+void Resource::SetIndex( bool re_stat )
 {
 	assert( m_parent->m_json != NULL );
 	if ( !m_json )
 		m_json = &((*m_parent->m_json)["tree"]).Item( Name() );
 	bool is_dir;
-	os::Stat( Path(), &m_ctime, NULL, &is_dir );
+	if ( re_stat )
+		os::Stat( Path(), &m_ctime, NULL, &is_dir );
 	if ( !is_dir )
 	{
 		m_json->Set( "ctime", Val( m_ctime.Sec() ) );
 		m_json->Set( "md5", Val( m_md5 ) );
 		m_json->Del( "tree" );
 	}
-	else // check if tree item exists
+	else
+	{
+		// add tree item if it does not exist
 		m_json->Item( "tree" );
+		m_json->Del( "md5" );
+	}
 }
 
 Resource::iterator Resource::begin() const
diff --git a/libgrive/src/base/Resource.hh b/libgrive/src/base/Resource.hh
index 354369f..531b78d 100644
--- a/libgrive/src/base/Resource.hh
+++ b/libgrive/src/base/Resource.hh
@@ -139,7 +139,7 @@ private :
 	
 	void DeleteLocal() ;
 	void DeleteIndex() ;
-	void SetIndex() ;
+	void SetIndex( bool ) ;
 	
 	void SyncSelf( Syncer* syncer, ResourceTree *res_tree, const Val& options ) ;
 
diff --git a/libgrive/src/http/CurlAgent.cc b/libgrive/src/http/CurlAgent.cc
index a527d51..4b23067 100644
--- a/libgrive/src/http/CurlAgent.cc
+++ b/libgrive/src/http/CurlAgent.cc
@@ -35,7 +35,6 @@
 #include <cassert>
 #include <cstring>
 #include <limits>
-#include <sstream>
 #include <streambuf>
 #include <iostream>
 
diff --git a/libgrive/src/http/Download.cc b/libgrive/src/http/Download.cc
index 885187e..26804e6 100644
--- a/libgrive/src/http/Download.cc
+++ b/libgrive/src/http/Download.cc
@@ -20,7 +20,6 @@
 #include "Download.hh"
 // #include "util/SignalHandler.hh"
 
-#include "Error.hh"
 #include "util/Crypt.hh"
 
 // boost headers
diff --git a/libgrive/src/http/Header.cc b/libgrive/src/http/Header.cc
index 9f0bdd3..6d875f9 100644
--- a/libgrive/src/http/Header.cc
+++ b/libgrive/src/http/Header.cc
@@ -22,6 +22,7 @@
 #include <algorithm>
 #include <iterator>
 #include <ostream>
+#include <sstream>
 
 namespace gr { namespace http {
 
@@ -34,6 +35,13 @@ void Header::Add( const std::string& str )
 	m_vec.push_back( str ) ;
 }
 
+std::string Header::Str() const
+{
+	std::ostringstream s ;
+	s << *this ;
+	return s.str() ;
+}
+
 Header::iterator Header::begin() const
 {
 	return m_vec.begin() ;
diff --git a/libgrive/src/http/Header.hh b/libgrive/src/http/Header.hh
index 2486cd0..844b6e6 100644
--- a/libgrive/src/http/Header.hh
+++ b/libgrive/src/http/Header.hh
@@ -37,6 +37,7 @@ public :
 	Header() ;
 	
 	void Add( const std::string& str ) ;
+	std::string Str() const ;
 	
 	iterator begin() const ;
 	iterator end() const ;
diff --git a/libgrive/src/util/Crypt.cc b/libgrive/src/util/Crypt.cc
index 5fb8ebe..b34494f 100644
--- a/libgrive/src/util/Crypt.cc
+++ b/libgrive/src/util/Crypt.cc
@@ -24,7 +24,6 @@
 #include "MemMap.hh"
 
 #include <iomanip>
-#include <sstream>
 
 // dependent libraries
 #include <gcrypt.h>
diff --git a/libgrive/src/util/DateTime.cc b/libgrive/src/util/DateTime.cc
index ffb4ec5..2fe7989 100644
--- a/libgrive/src/util/DateTime.cc
+++ b/libgrive/src/util/DateTime.cc
@@ -33,7 +33,6 @@
 #include <cassert>
 #include <cstdlib>
 #include <cstring>
-#include <iostream>
 #include <iomanip>
 
 #include <time.h>
diff --git a/libgrive/src/util/Exception.cc b/libgrive/src/util/Exception.cc
index 9cf6681..a4652f6 100644
--- a/libgrive/src/util/Exception.cc
+++ b/libgrive/src/util/Exception.cc
@@ -26,7 +26,6 @@
 
 #include <cstdlib>
 #include <iterator>
-#include <sstream>
 
 namespace gr {