Attempting to delete a data set in ArcCatalog fails and returns the message:
"Failed to delete selected object(s)."
The data may have read-only permissions.
Change the operating system permissions on the files you need to delete.
The Delete menu option is always enabled in ArcCatalog, as file permissions are only checked when actually executing the command. This behavior is by design and improves the overall performance of ArcCatalog.