Plone - Do Not Remove Anonymous View Access for /author Without Granting Authenticated View Access
I recently corrupted a Plone website by attempting to remove anonymous view access for the /author subdirectory without giving access to Authenticated users. That action resulted in the website being unusable.
In trying to hide what normally appears in Plone with the URL:
[your website url]/author/admin
I removed Anonymous View Access via:
/author/manage_access
Without also adding View Access for Authenticated users. That resulted in the entire website being unusable.
For a given item in Plone, someone must always have permissions, or nobody, including the Administrator, will have permission.

