Office 2013 has changed the way it interoperates with SharePoint document management features. Legacy versions of Office relied heavily on DAV as the mechanism to remotely manage the SharePoint document lifecycle. A very common information worker scenario is opening a document from a SharePoint Document Library as read only in an Office client application to review the contents and then deciding to enable editing. With control bars and Backstage view options in the Office clients, this workflow should be seamless by just clicking the appropriate action. If “require checkout” is enabled on the SharePoint Document Library, the “Check Out” option should also be available from the Office client application. In Office 2013, things have changed just enough to disrupt this normal document lifecycle management flow; especially if the workstation has limited connectivity to the internet.
If your Office client is constantly connected to the internet, you normally won’t see a problem managing documents from the Office applications. However, there are a myriad of circumstances that cause disconnected internet connectivity while still maintaining a stable LAN connection to SharePoint. These scenarios usually involve lab setups or development VMs that do not have an active connection to the internet or no internet connection at all. Office 2013 now favors HTTP/HTTPS over DAV and, with the introduction of subscription licensing models and accounts for Office, client applications now need to regularly communicate with public internet services to complete essential functions; especially in SharePoint Server interop situations. Actually, this is not entirely true. Office really only needs to *think* that it has an internet connection to complete subsequent requests whether they are on the internet or local network.
For this post, I am going to consider a Windows 7 workstation setup that is not connected to the internet, does have a stable LAN connection to the SharePoint Servers, and attempts to manage SharePoint documents from Office 2013 clients. In our test case, some essential document management features like check out, check in, discard check out, and version history may not work correctly and the culprit is Network Awareness. Network Awareness is an OS feature that allows network location switching (from, say, a wired to a wireless connection) and provides client applications the ability to check network status from a common API. Everyone is familiar with the yellow exclamation triangle that will display on the network icon in the system tray if a workstation is not connected to the internet (Figure 1). This is an extension of Network Awareness called Network Communication Status Indicator (NCSI – no, not the TV show :) ).
Office 2013 relies on NCSI to setup certain application states when clients such as Word and Excel are launched. If Office 2013 detects a “no internet access” state, functions such as SharePoint check out and check in may not work. In a closed network, this can cause problems for development or testing of features that need these document management services. An easy fix would obviously be to connect the workstation to the internet, but we’ll assume this isn’t an available option and discuss how we can restore full fidelity Office document management with SharePoint on a network with no internet access.
We’ve discussed Network Awareness and NCSI as the key to Office 2013 interoperating with SharePoint correctly, now let’s dive into the details. At the core, NCSI relies on a set of registry entries to probe and verify internet connectivity. The default values are set to check public internet resources to validate an active internet connection. Without access to the internet, NCSI cannot successfully check the default values and the OS reports that there is no internet access. Since the underlying resources are HTTP based, we can trick the OS into thinking that it has internet access by manipulating the registry values.