I am running Dynamics NAV 2013R2 on a Server 2008R2 with SQL2008 on the server. I recently rolled out some new computers running Windows 10 and Office 2016 and when we try to open documents from NAV it takes over a minute for the DotNet call to open the document on Word on the users computer. This problem seems to be isolated to the Windows 10/Office 2016 machines. When I run the same request on Windows 8.1Pro with Office 2013 it takes 10 seconds to open the file from the server. On the Windows 10 machine, if I browse to the document storage area on the server and select a word document it takes the same 10 seconds to open it. So the issues seems to be the DotNet call from NAV that is chocking. One last piece of additional information: In order to install the NAV client on a Windows 10 computer, we were required to installed DotNet 3.5 first because it is not native in Windows 10 by default. On some of the machines it was added using "Windows Features" and on another computer it was added from a separate install file. Neither seems to make a difference.