diff --git a/tryton/common/common.py b/tryton/common/common.py
index f80fe6969d..74ffc9d184 100644
--- a/tryton/common/common.py
+++ b/tryton/common/common.py
@@ -42,7 +42,8 @@ try:
 except ImportError:
     pytz = None
 
-from tryton.exceptions import TrytonServerError, TrytonError
+from tryton.exceptions import (TrytonServerError, TrytonError,
+    TrytonServerUnavailable)
 
 _ = gettext.gettext
 
@@ -1048,7 +1049,7 @@ def process_exception(exception, *args):
                     return True
             finally:
                 PLOCK.release()
-    elif isinstance(exception, socket.error):
+    elif isinstance(exception, (socket.error, TrytonServerUnavailable)):
         msg = ''
         if len(exception.args) > 2:
             msg = exception.args[1]
diff --git a/tryton/exceptions.py b/tryton/exceptions.py
index 6807420c6c..bac5bc1a53 100644
--- a/tryton/exceptions.py
+++ b/tryton/exceptions.py
@@ -5,6 +5,10 @@ from jsonrpc import Fault
 TrytonServerError = Fault
 
 
+class TrytonServerUnavailable(Exception):
+    pass
+
+
 class TrytonError(Exception):
 
     def __init__(self, faultCode):
diff --git a/tryton/gui/window/view_form/screen/screen.py b/tryton/gui/window/view_form/screen/screen.py
index e1a85fa7ad..cb3969eb3b 100644
--- a/tryton/gui/window/view_form/screen/screen.py
+++ b/tryton/gui/window/view_form/screen/screen.py
@@ -14,7 +14,7 @@ from tryton.signal_event import SignalEvent
 from tryton.common import node_attributes
 from tryton.config import CONFIG
 import tryton.common as common
-from tryton.exceptions import TrytonServerError
+from tryton.exceptions import TrytonServerError, TrytonServerUnavailable
 from tryton.jsonrpc import JSONEncoder
 from tryton.common.tdp import DomainParser
 
@@ -620,7 +620,7 @@ class Screen(SignalEvent):
             rpc.execute('model', 'ir.ui.view_tree_expanded_state',
                 'set_expanded', self.model_name, json_domain,
                 self.current_view.children_field, json_paths, rpc.CONTEXT)
-        except TrytonServerError:
+        except (TrytonServerError, TrytonServerUnavailable):
             pass
 
     def get_tree_domain(self, parent):
diff --git a/tryton/rpc.py b/tryton/rpc.py
index c75435932d..1965cc9ca5 100644
--- a/tryton/rpc.py
+++ b/tryton/rpc.py
@@ -1,5 +1,6 @@
 #This file is part of Tryton.  The COPYRIGHT file at the top level of
 #this repository contains the full copyright notices and license terms.
+import httplib
 import itertools
 import logging
 import socket
@@ -10,7 +11,7 @@ from tryton.jsonrpc import ServerProxy, Fault
 from tryton.fingerprints import Fingerprints
 from tryton.config import get_config_dir
 from tryton.ipc import Server as IPCServer
-from tryton.exceptions import TrytonServerError
+from tryton.exceptions import TrytonServerError, TrytonServerUnavailable
 
 CONNECTION = None
 _USER = None
@@ -114,7 +115,7 @@ def logout():
             logging.getLogger('rpc.request').info('common.db.logout(%s, %s)' %
                 (_USER, _SESSION))
             CONNECTION.common.db.logout(_USER, _SESSION)
-        except (Fault, socket.error):
+        except (Fault, socket.error, httplib.CannotSendRequest):
             pass
         finally:
             _SEMAPHORE.release()
@@ -176,6 +177,8 @@ def _execute(blocking, *args):
         args = (_USER, _SESSION) + args[3:]
         logging.getLogger('rpc.request').info('%s%s' % (name, args))
         result = getattr(CONNECTION, name)(*args)
+    except httplib.CannotSendRequest, exception:
+        raise TrytonServerUnavailable(exception)
     finally:
         _SEMAPHORE.release()
     if key and method == 'fields_view_get':