We're having strange issue. We use RDP files generated in RDP client, we then sign those using rdpsign.exe.
Recently after upgrading our infrastructure from W8/2012 to W8.1/2012R2 we noticed that every RDP file generated in RDC 8.1 client contains a special character on first position that is not visible in normal text editor and is only visible in hex editor. This character wasn't there in W8/2012. When I create the RDP file manually (typing (copy/pasting) all the options in a text file), it doesn't contain any special character, but when I later sign that file file rdpsign, it adds that character again.
How do we get rid of it? It's preventing our provisioning system from substituting username.