diff --git a/addons/board/static/src/js/dashboard.js b/addons/board/static/src/js/dashboard.js
index e9dec85739f..80d418de6dc 100644
--- a/addons/board/static/src/js/dashboard.js
+++ b/addons/board/static/src/js/dashboard.js
@@ -172,8 +172,8 @@ var DashBoard = form_common.FormWidget.extend({
             board.columns.push(actions);
         });
         var arch = QWeb.render('DashBoard.xml', board);
-        this.rpc('/web/view/add_custom', {
-            view_id: this.view.fields_view.view_id,
+        this.rpc('/web/view/edit_custom', { // do not forward-port > saas-15
+            custom_id: this.view.fields_view.custom_view_id, // do not forward-port > saas-15
             arch: arch
         }).then(function() {
             data_manager.invalidate();
diff --git a/addons/web/controllers/main.py b/addons/web/controllers/main.py
index d99395c6032..6122b00e0ed 100644
--- a/addons/web/controllers/main.py
+++ b/addons/web/controllers/main.py
@@ -927,14 +927,18 @@ class DataSet(http.Controller):
 
 class View(http.Controller):
 
-    @http.route('/web/view/add_custom', type='json', auth="user")
-    def add_custom(self, view_id, arch):
-        CustomView = request.env['ir.ui.view.custom']
-        CustomView.create({
-            'user_id': request.session.uid,
-            'ref_id': view_id,
-            'arch': arch
-        })
+    @http.route('/web/view/edit_custom', type='json', auth="user")
+    def edit_custom(self, custom_id, arch):
+        """
+        Edit a custom view
+
+        :param int custom_id: the id of the edited custom view
+        :param str arch: the edited arch of the custom view
+        :returns: dict with acknowledged operation (result set to True)
+        """
+
+        custom_view = request.env['ir.ui.view.custom'].browse(custom_id)
+        custom_view.write({ 'arch': arch })
         return {'result': True}
 
 class TreeView(View):
diff --git a/odoo/addons/base/i18n/base.pot b/odoo/addons/base/i18n/base.pot
index 026f23c5b98..957d4990175 100644
--- a/odoo/addons/base/i18n/base.pot
+++ b/odoo/addons/base/i18n/base.pot
@@ -11466,6 +11466,18 @@ msgstr ""
 msgid "Memos pad"
 msgstr ""
 
+#. module: base
+#: code:addons/base/ir/ir_model.py:382
+#, python-format
+msgid "Model %s does not exist"
+msgstr ""
+
+#. module: base
+#: code:addons/base/ir/ir_model.py:383
+#, python-format
+msgid "Please specify a valid model for the object relation"
+msgstr ""
+
 #. module: base
 #: model:ir.model.fields,field_description:base.field_ir_ui_menu_name
 #: model:ir.ui.view,arch_db:base.edit_menu
diff --git a/odoo/addons/base/ir/ir_model.py b/odoo/addons/base/ir/ir_model.py
index cbeb6f2b399..3ab7d494c1f 100644
--- a/odoo/addons/base/ir/ir_model.py
+++ b/odoo/addons/base/ir/ir_model.py
@@ -393,6 +393,13 @@ class IrModelFields(models.Model):
     def _onchange_ttype(self):
         self.copy = (self.ttype != 'one2many')
         if self.ttype == 'many2many' and self.model_id and self.relation:
+            if self.relation not in self.env:
+                return {
+                    'warning': {
+                        'title': _('Model %s does not exist') % self.relation,
+                        'message': _('Please specify a valid model for the object relation'),
+                    }
+                }
             names = self._custom_many2many_names(self.model_id.model, self.relation)
             self.relation_table, self.column1, self.column2 = names
         else: