The index don't exist. Available indexes on a Folder are:
Creator
Date
Description
SearchableText
Subject
Title
Type
UID
allowedRolesAndUsers
cmf_uid
commentators
created
effective
effectiveRange
end
expires
getId
getObjPositionInParent
getRawRelatedItems
id
in_reply_to
is_default_page
is_folderish
meta_type
modified
object_provides
path
portal_type
review_state
sortable_title
start
sync_uid
total_comments
Changing plone/app/content/browser/contents/__init__.py so:
--- __init__.py.ori 2017-12-25 23:19:33.351624000 +0100
+++ __init__.py 2018-01-17 11:56:01.438211350 +0100
@@ -179,7 +179,6 @@
'in_response_to',
'listCreators',
'meta_type',
- 'modified',
'portal_type',
'sync_uid'
]
@@ -200,7 +199,7 @@
'is_folderish': translate(_('Folder'), context=self.request),
'last_comment_date': translate(_('Last comment date'), context=self.request), # noqa
'location': translate(_('Location'), context=self.request),
- 'ModificationDate': translate(_('Last modified'), context=self.request), # noqa
+ 'modified': translate(_('Last modified'), context=self.request), # noqa
'review_state': translate(_('Review state'), context=self.request), # noqa
'start': translate(_('Start Date'), context=self.request),
'Subject': translate(_('Tags'), context=self.request),
@@ -246,7 +245,6 @@
'getRawRelatedItems',
'in_reply_to',
'meta_type',
- 'modified',
'object_provides',
'portal_type',
'SearchableText',
@@ -264,7 +262,7 @@
'expires': translate(_('Expiration date'), context=self.request),
'id': translate(_('ID'), context=self.request),
'is_folderish': translate(_('Folder'), context=self.request),
- 'ModificationDate': translate(_('Last modified'), context=self.request), # noqa
+ 'modified': translate(_('Last modified'), context=self.request), # noqa
'review_state': translate(_('Review state'), context=self.request),
'sortable_title': translate(_('Title'), context=self.request),
'start': translate(_('Start Date'), context=self.request),
@@ -341,7 +339,7 @@
'is_folderish',
'last_comment_date',
'location',
- 'ModificationDate',
+ 'modified',
'path',
'portal_type',
'review_state',