You may find some content in the portal that doesn't work as expected in your ArcGIS Desktop application. A common reason is that the content owner has shared a map or layer without sharing the underlying data to everyone who can access the map or layer. Layer files (.lyr, .lyrx) and map documents (.mxd, .mapx) are especially prone to this. For these types of files to be useful as publicly shared items in the portal, the data associated with the file needs to be accessible to everybody who has access to the portal. For example, a layer file needs to reference a map service that is shared in the portal or an OGC WMS service that is available on your intranet.
If you open a layer file or map document in your ArcGIS Desktopapplication and see missing layers, it is likely that you don't have access to all the underlying data sources. You may want to add a comment to the item about the missing data. This will help other users gauge the usefulness of the item. You may also consider searchingfor the equivalent geographic information as a layer package, map service, or map.
Package files, such as a map package, are a good way to share cartography and data because they contain both the map or tool definition information and data contents.
Services from ArcGIS Server are another good way to share content as long as the services are on a publicly available server. An additional advantage of services is that they can be used as web layers for maps.