diff --git a/libgrive/src/drive/Drive.cc b/libgrive/src/drive/Drive.cc
index 98f6833..84b1f55 100644
--- a/libgrive/src/drive/Drive.cc
+++ b/libgrive/src/drive/Drive.cc
@@ -183,7 +183,8 @@ std::cout << "local " << path << " is newer" << std::endl ;
 				// re-reading the file
 				ifile.seekg(0) ;
 				
-				file.Upload( ifile.rdbuf(), m_http_hdr ) ;
+				if ( !file.Upload( ifile.rdbuf(), m_http_hdr ) )
+std::cout << path << " is read only" << std::endl ;
 			}
 		}
 	}
diff --git a/libgrive/src/drive/File.cc b/libgrive/src/drive/File.cc
index 14cf37d..1b9e78e 100644
--- a/libgrive/src/drive/File.cc
+++ b/libgrive/src/drive/File.cc
@@ -56,8 +56,9 @@ void File::Update( const Json& entry )
 		FindInArray( "scheme", "http://schemas.google.com/g/2005#kind", node )
 		? node["label"].Str() : std::string() ;
 	
-	m_upload_link		= entry["link"].FindInArray( "rel",
-  		"http://schemas.google.com/g/2005#resumable-edit-media" )["href"].Str() ;
+	m_upload_link		= entry["link"].
+		FindInArray( "rel", "http://schemas.google.com/g/2005#resumable-edit-media", node )
+		? node["href"].Str() : std::string() ;
 
   	// convert to lower case for easy comparison
 	std::transform(
@@ -115,8 +116,12 @@ void File::Download( const Path& file, const http::Headers& auth ) const
 	os::SetFileTime( file, m_server_modified ) ;
 }
 
-void File::Upload( std::streambuf *file, const http::Headers& auth )
+bool File::Upload( std::streambuf *file, const http::Headers& auth )
 {
+	// upload link missing means that file is read only
+	if ( m_upload_link.empty() )
+		return false ;
+
 	std::string meta =
 	"<?xml version='1.0' encoding='UTF-8'?>\n"
 	"<entry xmlns=\"http://www.w3.org/2005/Atom\" xmlns:docs=\"http://schemas.google.com/docs/2007\">"
@@ -148,6 +153,7 @@ void File::Upload( std::streambuf *file, const http::Headers& auth )
 	uphdr.push_back( "Accept:" ) ;
 	
 	http.Put( http.RedirLocation(), data, uphdr ) ;
+	return true ;
 }
 
 } // end of namespace
diff --git a/libgrive/src/drive/File.hh b/libgrive/src/drive/File.hh
index 2727882..2346a29 100644
--- a/libgrive/src/drive/File.hh
+++ b/libgrive/src/drive/File.hh
@@ -48,7 +48,7 @@ public :
 	std::string Parent() const ;
 	
 	void Download( const Path& file, const http::Headers& auth ) const ;
-	void Upload( std::streambuf *file, const http::Headers& auth ) ;
+	bool Upload( std::streambuf *file, const http::Headers& auth ) ;
 
 private :
 	void Update( const Json& entry ) ;