ManagementForm data is missing or has been tampered with

Question

Suddenly, after 7 weeks, I get this error

ValidationError: [u'ManagementForm data is missing or has been tampered with']

It worked fine for several weeks. I did not change a thing. This happens when I'm trying to save a page.

Stacktrace (most recent call last):

  File "django/core/handlers/base.py", line 115, in get_response
    response = callback(request, *callback_args, **callback_kwargs)
  File "django/contrib/admin/options.py", line 372, in wrapper
    return self.admin_site.admin_view(view)(*args, **kwargs)
  File "django/utils/decorators.py", line 91, in _wrapped_view
    response = view_func(request, *args, **kwargs)
  File "django/views/decorators/cache.py", line 89, in _wrapped_view_func
    response = view_func(request, *args, **kwargs)
  File "django/contrib/admin/sites.py", line 202, in inner
    return view(request, *args, **kwargs)
  File "feincms/module/page/modeladmins.py", line 167, in change_view
    return super(PageAdmin, self).change_view(request, object_id, **kwargs)
  File "feincms/admin/item_editor.py", line 229, in change_view
    return super(ItemEditor, self).change_view(request, object_id, **kwargs)
  File "django/utils/decorators.py", line 25, in _wrapper
    return bound_func(*args, **kwargs)
  File "django/utils/decorators.py", line 91, in _wrapped_view
    response = view_func(request, *args, **kwargs)
  File "django/utils/decorators.py", line 21, in bound_func
    return func(self, *args2, **kwargs2)
  File "django/db/transaction.py", line 223, in inner
    return func(*args, **kwargs)
  File "django/contrib/admin/options.py", line 1100, in change_view
    queryset=inline.queryset(request))
  File "django/forms/models.py", line 720, in __init__
    queryset=qs, **kwargs)
  File "django/forms/models.py", line 441, in __init__
    super(BaseModelFormSet, self).__init__(**defaults)
  File "django/forms/formsets.py", line 56, in __init__
    self._construct_forms()
  File "django/forms/formsets.py", line 123, in _construct_forms
    for i in xrange(min(self.total_form_count(), self.absolute_max)):
  File "django/forms/formsets.py", line 97, in total_form_count
    return self.management_form.cleaned_data[TOTAL_FORM_COUNT]
  File "django/forms/formsets.py", line 85, in management_form
    raise ValidationError('ManagementForm data is missing or has been tampered with')

Does anyone has a clue?

I'm using django 1.5 and FeinCMS 1.7.0

Answer 1

I had 2 different versions of FeinCMS installed. Deleting both and installing a fresh FeinCMS solved this problem.