diff --git a/account.py b/account.py
index c082ccd405..a33023fae4 100644
--- a/account.py
+++ b/account.py
@@ -8,6 +8,7 @@ from sql.aggregate import Sum
 from sql.conditionals import Coalesce
 
 from trytond import backend
+from trytond.i18n import gettext
 from trytond.model import (ModelView, ModelSQL, DeactivableMixin, fields,
     Unique, tree)
 from trytond.wizard import Wizard, StateView, StateAction, Button
@@ -15,6 +16,8 @@ from trytond.pyson import Eval, If, PYSONEncoder, PYSONDecoder
 from trytond.transaction import Transaction
 from trytond.pool import Pool
 
+from .exceptions import AccountValidationError, RootValidationError
+
 __all__ = ['Account', 'AccountDistribution',
     'OpenChartAccountStart', 'OpenChartAccount',
     'AnalyticAccountEntry', 'AnalyticMixin']
@@ -109,11 +112,6 @@ class Account(
         super(Account, cls).__setup__()
         cls._order.insert(0, ('code', 'ASC'))
         cls._order.insert(1, ('name', 'ASC'))
-        cls._error_messages.update({
-                'invalid_distribution': (
-                    'The distribution sum of account "%(account)s" '
-                    'is not 100%%.'),
-                })
 
     @classmethod
     def __register__(cls, module_name):
@@ -153,9 +151,9 @@ class Account(
         if self.type != 'distribution':
             return
         if sum((d.ratio for d in self.distributions)) != 1:
-            self.raise_user_error('invalid_distribution', {
-                    'account': self.rec_name,
-                    })
+            raise AccountValidationError(
+                gettext('analytic_account.msg_invalid_distribution',
+                    account=self.rec_name))
 
     @fields.depends('company')
     def on_change_with_currency(self, name=None):
@@ -447,7 +445,7 @@ class AnalyticAccountEntry(ModelView, ModelSQL):
         t = cls.__table__()
         cls._sql_constraints += [
             ('root_origin_uniq', Unique(t, t.origin, t.root),
-                'Only one account is allowed per analytic root and origin.'),
+                'analytic_account.msg_root_origin_unique'),
             ]
 
     @classmethod
@@ -502,14 +500,6 @@ class AnalyticMixin(object):
     analytic_accounts_size = fields.Function(fields.Integer(
             'Analytic Accounts Size'), 'get_analytic_accounts_size')
 
-    @classmethod
-    def __setup__(cls):
-        super(AnalyticMixin, cls).__setup__()
-        cls._error_messages.update({
-                'root_account': ('Some mandatory root account are missing '
-                    'on "%(name)s"'),
-                })
-
     @classmethod
     def __register__(cls, module_name):
         pool = Pool()
@@ -591,7 +581,10 @@ class AnalyticMixin(object):
             for mandatory in all_mandatory_roots:
                 if mandatory.company in companies:
                     mandatory_roots.add(mandatory)
-            if not mandatory_roots <= analytic_roots:
-                cls.raise_user_error('root_account', {
-                        'name': analytic.rec_name,
-                        })
+            mandatory_roots.difference_update(analytic_roots)
+            if mandatory_roots:
+                raise RootValidationError(
+                    gettext('analytic_account.msg_missing_root_account',
+                        name=analytic.rec_name,
+                        analytics=', '.join(
+                            (r.rec_name for r in mandatory_roots))))
diff --git a/exceptions.py b/exceptions.py
new file mode 100644
index 0000000000..671304ce46
--- /dev/null
+++ b/exceptions.py
@@ -0,0 +1,12 @@
+# This file is part of Tryton.  The COPYRIGHT file at the top level of
+# this repository contains the full copyright notices and license terms.
+
+from trytond.model.exceptions import ValidationError
+
+
+class AccountValidationError(ValidationError):
+    pass
+
+
+class RootValidationError(ValidationError):
+    pass
diff --git a/line.py b/line.py
index 9a1c710ba0..3721f6c295 100644
--- a/line.py
+++ b/line.py
@@ -46,15 +46,8 @@ class Line(ModelSQL, ModelView):
             ('credit_debit',
                 Check(t,
                     (t.credit * t.debit == 0) & (t.credit + t.debit >= 0)),
-                'Wrong credit/debit values.'),
+                'account.msg_line_debit_credit'),
             ]
-        cls._error_messages.update({
-                'line_on_view_account': (
-                    'You can not create a move line using '
-                    'view account "%s".'),
-                'line_on_inactive_account': ('You can not create a move line '
-                    'using inactive account "%s".'),
-                })
         cls._order.insert(0, ('date', 'ASC'))
 
     @classmethod
@@ -144,20 +137,6 @@ class Line(ModelSQL, ModelView):
         MoveLine.set_analytic_state(move_lines)
         MoveLine.save(move_lines)
 
-    @classmethod
-    def validate(cls, lines):
-        super(Line, cls).validate(lines)
-        for line in lines:
-            line.check_account()
-
-    def check_account(self):
-        if self.account.type == 'view':
-            self.raise_user_error('line_on_view_account',
-                (self.account.rec_name,))
-        if not self.account.active:
-            self.raise_user_error('line_on_inactive_account',
-                (self.account.rec_name,))
-
 
 class Move(metaclass=PoolMeta):
     __name__ = 'account.move'
diff --git a/message.xml b/message.xml
new file mode 100644
index 0000000000..8afd274e7d
--- /dev/null
+++ b/message.xml
@@ -0,0 +1,16 @@
+<?xml version="1.0"?>
+<!-- This file is part of Tryton.  The COPYRIGHT file at the top level of
+this repository contains the full copyright notices and license terms. -->
+<tryton>
+    <data group="1">
+        <record model="ir.message" id="msg_invalid_distribution">
+            <field name="text">To save account "%(account)s" the sum of their distributions must be 100%%.</field>
+        </record>
+        <record model="ir.message" id="msg_missing_root_account">
+            <field name="text">To save "%(name)s" you must set a value for analytics "%(analytics)s".</field>
+        </record>
+        <record model="ir.message" id="msg_root_origin_unique">
+            <field name="text">Only one account is allowed by analytic root and origin.</field>
+        </record>
+    </data>
+</tryton>
diff --git a/tryton.cfg b/tryton.cfg
index da1f4280fd..9f4a2b899c 100644
--- a/tryton.cfg
+++ b/tryton.cfg
@@ -12,3 +12,4 @@ xml:
     account.xml
     line.xml
     rule.xml
+    message.xml