Here is the trace : 2013-11-06 09:19:32,434 8684 10500 ERROR nxdrive.synchronizer Failed to sync LastKnownState<local_folder=u'Nuxeo Driv e', local_path=u'/dossier DSI/texte_simple_1.txt', remote_name=None, local_state=u'created', remote_state=u'unknown', pa ir_state=u'locally_created'>, blacklisting doc pair for 300 seconds Traceback (most recent call last): File "nuxeo-drive-client\nxdrive\synchronizer.py", line 1034, in synchronize File "nuxeo-drive-client\nxdrive\synchronizer.py", line 573, in synchronize_one File "nuxeo-drive-client\nxdrive\synchronizer.py", line 693, in synchronize_locally_created File "nuxeo-drive-client\nxdrive\client\remote_file_system_client.py", line 120, in stream_file File "nuxeo-drive-client\nxdrive\client\base_automation_client.py", line 301, in execute_with_blob_streaming File "nuxeo-drive-client\nxdrive\client\base_automation_client.py", line 372, in execute_batch File "nuxeo-drive-client\nxdrive\client\base_automation_client.py", line 209, in execute File "C:\Python27\lib\urllib2.py", line 406, in open File "C:\Python27\lib\urllib2.py", line 519, in http_response File "C:\Python27\lib\urllib2.py", line 444, in error File "C:\Python27\lib\urllib2.py", line 378, in call_chain File "C:\Python27\lib\urllib2.py", line 527, in http_error_default HTTPError: HTTP Error 500: Erreur Interne de Servlet

OK this is consistent with your previous comment, HTTP 500 means a server-side error.