RDS Server 2008 Browser Not Supported In IE10 and IE11
2) Open Up IIS Management Console.
3) Branch out the sites and then left click on RDweb. On the right hand side double click on HTTP Response Headers.
5) On the box that appears enter :-
Now do a IISRESET on the server and you should be good to go..
UPDATE : If you have any pending windows updates also install these as sometimes it wont work until they are installed and also restart the server if IISRESET does not work.