Updating the site content type failed
To create site content types for the top-level site in a site collection, you must be a site collection administrator.
You can specify the properties or metadata that you want to collect for an item of a specific content type by adding columns to the site content type.Changes that you make to a site content type do not affect the parent site content type from which the site content type was created.Top of Page You can associate a document template only with a document content type (any content type derived from the document parent content type).For example, your organization might want to track a specific set of metadata for all of its purchase orders, such as account number, project number, and project manager.If you add columns for account number, project number, and project manager to the purchase order content type, users are prompted to provide this metadata for items of this content type.When the document is saved to the server, this property is automatically updated in the Status column for the library.
Site administrators can enable document conversion so that end users can convert documents of one file type into another format.
Content types that are defined at the site level are called site content types.
Site content types are available for use in any subsites of the site for which they have been defined.
Document conversion for site content types also enables site administrators to configure content types to store settings that define which converters are available and how those converters work on documents of that content type.
A number of document converters are included with the application, and your organization might have additional custom converters as well.
When you define a new custom site content type in the Site Content Type Gallery for a site, you start by choosing an existing parent site content type in the Site Content Type Gallery as your starting point.