We recently switched to using DFS for our Fileshares, but quickly ran into a problem with Microsoft Office Documents opening up in “Protected Mode”.
The reason given was that Word and Excel believed the files originated from the Internet, and therefore was warning users each time they opened a document from the DFS Share.
I had already added my DFS URL as a “Trusted Location”, but this is not sufficient.
The extra step required is to add the Local Domain into the “Local Intranet” Zone within Internet Explorer.
This can either be done manually (for each user), or via a GPO as follows:
Within the GPO: Computer Configuration => Administrator Templates => Windows Components => Internet Explorer => Internet Control Panel => Security Page => Site to Zone Assignment List:
Value Name = Your Local Domain (eg \\local.mydomain.co.uk\)
Value = 1 (Intranet Zone)
That should fix any issues involving “Protected Mode”.