diff --git a/babi_multiprocess.diff b/babi_multiprocess.diff
index d72377f..a2d01b7 100644
--- a/babi_multiprocess.diff
+++ b/babi_multiprocess.diff
@@ -19,11 +19,35 @@ index 407ff358..0be2a41a 100644
              raise
  
      def add(self, cls, type='model'):
-diff --git a/tryton/trytond/trytond/model/modelsql.py b/trytond/trytond/model/modelsql.py
-index d762a27a..5ca47c34 100644
+diff --git a/tryton/trytond/trytond/model/modelsql.py b/tryton/trytond/trytond/model/modelsql.py
+index d4abf5dfe6..29da9fa56b 100644
 --- a/tryton/trytond/trytond/model/modelsql.py
 +++ b/tryton/trytond/trytond/model/modelsql.py
-@@ -1429,8 +1429,14 @@ class ModelSQL(ModelStorage):
+@@ -957,6 +957,7 @@ class ModelSQL(ModelStorage):
+         extra_fields = set()
+         if 'write_date' not in fields_names:
+             extra_fields.add('write_date')
++        fields_names = fields_names[:]
+         for field_name in fields_names:
+             if field_name in {'_timestamp', '_write', '_delete'}:
+                 continue
+@@ -966,7 +967,14 @@ class ModelSQL(ModelStorage):
+             if field_name.endswith(':string'):
+                 field_name = field_name[:-len(':string')]
+                 fields_related[field_name]
+-            field = cls._fields[field_name]
++            try:
++                field = cls._fields[field_name]
++            except KeyError as err:
++                if 'babi_' in str(err):
++                    fields_names.remove(field_name)
++                    continue
++                else:
++                    raise
+             if hasattr(field, 'datetime_field') and field.datetime_field:
+                 extra_fields.add(field.datetime_field)
+             if field.context:
+@@ -1435,8 +1443,14 @@ class ModelSQL(ModelStorage):
                  foreign_table = Model.__table__()
                  foreign_red_sql = reduce_ids(
                      Column(foreign_table, field_name), sub_ids)