On a server that is running Microsoft SharePoint Server 2010, you create a document library that uses a document set as a content type.
You locate the document set settings for the document set content type, and you mark a column as shared.
The column that is marked as a shared column is also on another content type that is an allowed content type for the document set.
You set Require Check Out to Yes for the document library Versioning Settings.
The column is a required column either on the content type that is an allowed content type in the document set or at the site level.
In this scenario, the operation fails when users try to edit or create items of the content type that is an allowed content type for the document set.
This issue occurs because shared columns in a document set are marked as hidden and read-only. When a client application tries to upload a document into this document set, the shared column cannot be set, and this causes the upload operation to fail.
To work around this issue, do not set shared columns as Required in document set content types. Instead, set the columns as Optional.