diff --git a/odoo/addons/base/models/ir_fields.py b/odoo/addons/base/models/ir_fields.py
index 80f3ce31513..8dc639b2ee1 100644
--- a/odoo/addons/base/models/ir_fields.py
+++ b/odoo/addons/base/models/ir_fields.py
@@ -24,7 +24,6 @@ class ImportWarning(Warning):
 class ConversionNotFound(ValueError):
     pass
 
-
 class IrFieldsConverter(models.AbstractModel):
     _name = 'ir.fields.converter'
     _description = 'Fields Converter'
@@ -113,6 +112,8 @@ class IrFieldsConverter(models.AbstractModel):
                             # uniform handling
                             w = ImportWarning(w)
                         log(field, w)
+                except (UnicodeEncodeError, UnicodeDecodeError) as e:
+                    log(field, ValueError(str(e)))
                 except ValueError as e:
                     if import_file_context:
                         # if the error is linked to a matching error, the error is a tuple
diff --git a/odoo/addons/test_impex/ir.model.access.csv b/odoo/addons/test_impex/ir.model.access.csv
index e051b726705..a901be2bf30 100644
--- a/odoo/addons/test_impex/ir.model.access.csv
+++ b/odoo/addons/test_impex/ir.model.access.csv
@@ -26,3 +26,5 @@ access_export_one2many_recursive,access_export_one2many_recursive,model_export_o
 access_export_unique,access_export_unique,model_export_unique,,1,1,1,1
 access_export_inherits_parent,access_export_inherits_parent,model_export_inherits_parent,,1,1,1,1
 access_export_inherits_child,access_export_inherits_child,model_export_inherits_child,,1,1,1,1
+access_export_m2o_str,access_export_m2o_str,model_export_m2o_str,,1,1,1,1
+access_export_m2o_str_child,access_export_m2o_str_child,model_export_m2o_str_child,,1,1,1,1
diff --git a/odoo/addons/test_impex/models.py b/odoo/addons/test_impex/models.py
index 685cec9b80e..9a2fdf40392 100644
--- a/odoo/addons/test_impex/models.py
+++ b/odoo/addons/test_impex/models.py
@@ -174,3 +174,13 @@ class InheritsChild(models.Model):
 
     parent_id = fields.Many2one('export.inherits.parent', required=True, ondelete='cascade')
     value = fields.Integer()
+
+class Many2String(models.Model):
+    _name = _description = 'export.m2o.str'
+
+    child_id = fields.Many2one('export.m2o.str.child')
+
+class ChidToString(models.Model):
+    _name = _description = 'export.m2o.str.child'
+
+    name = fields.Char()
diff --git a/odoo/addons/test_impex/tests/test_load.py b/odoo/addons/test_impex/tests/test_load.py
index bc989799532..daf53f2b4e2 100644
--- a/odoo/addons/test_impex/tests/test_load.py
+++ b/odoo/addons/test_impex/tests/test_load.py
@@ -737,6 +737,20 @@ class test_m2o(ImporterCase):
         self.assertFalse(result['messages'])
         self.assertEqual(len(result['ids']), 1)
 
+class TestInvalidStrings(ImporterCase):
+    model_name = 'export.m2o.str'
+
+    @mute_logger('odoo.sql_db')
+    def test_fail_unpaired_surrogate(self):
+        result = self.import_(['child_id'], [['\uddff']])
+        self.assertTrue(result['messages'])
+        self.assertIn('surrogates', result['messages'][0]['message'])
+
+    @mute_logger('odoo.sql_db')
+    def test_fail_nul(self):
+        result = self.import_(['child_id'], [['\x00']])
+        self.assertTrue(result['messages'])
+        self.assertIn('NUL', result['messages'][0]['message'])
 
 class test_m2m(ImporterCase):
     model_name = 'export.many2many'
diff --git a/odoo/models.py b/odoo/models.py
index 06bb0698f28..a920d1f192b 100644
--- a/odoo/models.py
+++ b/odoo/models.py
@@ -1312,13 +1312,14 @@ class BaseModel(metaclass=MetaModel):
             exc_vals = dict(base, record=record, field=field_name)
             record = dict(base, type=type, record=record, field=field,
                           message=str(exception.args[0]) % exc_vals)
-            # ensure to add field_name to the exception. Used in import to concatenate multiple errors in the same block
             if len(exception.args) > 1:
-                if not exception.args[1]:
-                    exception.args = (exception.args[0], {'field_name': field_name})
-                else:
-                    exception.args[1]['field_name'] = field_name
-                record.update(exception.args[1])
+                info = {}
+                if exception.args[1] and isinstance(exception.args[1], dict):
+                    info = exception.args[1]
+                # ensure field_name is added to the exception. Used in import to
+                # concatenate multiple errors in the same block
+                info['field_name'] = field_name
+                record.update(info)
             log(record)
 
         stream = CountingStream(records)