Hi,

I am trying to go to settings page and getting a weird error. I can't go to settings of any of the modules installed like Purchase, Sales, Manufacturing, Inventory, General Settings. 

I am getting the following error:

 File "D:\odoo-12.0\odoo\tools\cache.py", line 88, in lookup
    r = d[key]
  File "D:\odoo-12.0\odoo\tools\func.py", line 69, in wrapper
    return func(self, *args, **kwargs)
  File "D:\odoo-12.0\odoo\tools\lru.py", line 44, in __getitem__
    a = self.d[obj].me
KeyError: ('ir.model.data', <function IrModelData.xmlid_lookup at 0x000000533E34DBF8>, 'sale.group_discount_per_so_line')
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
 File "D:\odoo-12.0\odoo\http.py", line 656, in _handle_exception
    return super(JsonRequest, self)._handle_exception(exception)
  File "D:\odoo-12.0\odoo\http.py", line 314, in _handle_exception
    raise pycompat.reraise(type(exception), exception, sys.exc_info()[2])
  File "D:\odoo-12.0\odoo\tools\pycompat.py", line 87, in reraise
    raise value
  File "D:\odoo-12.0\odoo\http.py", line 698, in dispatch
    result = self._call_function(**self.params)
  File "D:\odoo-12.0\odoo\http.py", line 346, in _call_function
    return checked_call(self.db, *args, **kwargs)
  File "D:\odoo-12.0\odoo\service\model.py", line 98, in wrapper
    return f(dbname, *args, **kwargs)
  File "D:\odoo-12.0\odoo\http.py", line 339, in checked_call
    result = self.endpoint(*a, **kw)
  File "D:\odoo-12.0\odoo\http.py", line 941, in __call__
    return self.method(*args, **kw)
  File "D:\odoo-12.0\odoo\http.py", line 519, in response_wrap
    response = f(*args, **kw)
  File "d:\odoo-12.0\addons\web\controllers\main.py", line 962, in call_kw
    return self._call_kw(model, method, args, kwargs)
  File "d:\odoo-12.0\addons\web\controllers\main.py", line 954, in _call_kw
    return call_kw(request.env[model], method, args, kwargs)
  File "D:\odoo-12.0\odoo\api.py", line 755, in call_kw
    return _call_kw_model(method, model, args, kwargs)
  File "D:\odoo-12.0\odoo\api.py", line 728, in _call_kw_model
    result = method(recs, *args, **kwargs)
  File "d:\odoo-12.0\odoo\addons\base\models\res_config.py", line 497, in default_get
    classified = self._get_classified_fields()
  File "d:\odoo-12.0\odoo\addons\base\models\res_config.py", line 472, in _get_classified_fields
    groups.append((name, field_groups, ref(field.implied_group)))
  File "D:\odoo-12.0\odoo\api.py", line 864, in ref
    return self['ir.model.data'].xmlid_to_object(xml_id, raise_if_not_found=raise_if_not_found)
  File "d:\odoo-12.0\odoo\addons\base\models\ir_model.py", line 1433, in xmlid_to_object
    t = self.xmlid_to_res_model_res_id(xmlid, raise_if_not_found)
  File "d:\odoo-12.0\odoo\addons\base\models\ir_model.py", line 1417,
po
\odoo-12.0\odoo\tools\cache.py", line 93, in lookup
    value = d[key] = self.method(*args, **kwargs)
  File "d:\odoo-12.0\odoo\addons\base\models\ir_model.py", line 1406, in xmlid_lookup
    raise ValueError('External ID not found in the system: %s' % xmlid)
ValueError: External ID not found in the system: sale.group_discount_per_so_line

Odoo Server Error

Traceback (most recent call last):

Where am I going wrong? Please assist.