Error while trying to determine RSS status of the item


Description

While working with media items, the following errors may appear in the log files:
WARN  The standard values field of template /sitecore/templates/System/Media/Versioned/Image:{C97BA923-8009-4858-BDD5-D8BE5FCCECF7} does not contain an ID that points to a child
ERROR Error while trying to determine RSS status of the item. The likely reason is that standard values reference of the template is broken. RSS 'Design' button is disabled. Item: /sitecore/media library/path/to/item
Exception: System.NullReferenceException
Message: Object reference not set to an instance of an object.
Source: Sitecore.Kernel
   at Sitecore.Syndication.RenderingAssignmentStrategy.GetStandardValuesItem(Item contentItem)
   at Sitecore.Syndication.RenderingAssignmentStrategy.GetTarget(Boolean create)
   at Sitecore.Syndication.RenderingAssignmentStrategy.TryGetTarget()
   at Sitecore.Shell.Applications.Feeds.Commands.SetFeedPresentation.QueryState(CommandContext context)

This issue occurs due to the following Media item templates having wrong Standard Values:

Solution

This issue does not have any negative impact on a regular work with media items.

However, if you would like such media items to be available through the RSS feed, this error may prevent you from setting up the appropriate item presentation.

To fix this problem, you should manually set the Standard Values field (Advanced section) of each aforementioned Media template to the corresponding __Standard Values item.