Installing applications on an RD Session Host server
As soon as you take a Windows Server and turn it into a Remote Desktop Session Host server to be used within an RDS environment, the way that applications work on that server changes significantly. Whenever programs and apps are installed onto that RDSH, it first needs to be put into a special Install Mode. Placing the server into Install Mode prior to launching the program installer is important to make sure that the applications are going to be installed in a way that will allow multiple users to run them simultaneously. Remember, our RDSH servers will be hosting multiple user sessions, probably dozens of them.
Using Install Mode is so important to applications working properly on an RDSH, that you really should not install any programs onto the server before you turn it into an RDSH. Once that role has been established, then apps can be safely installed, as long as you are using Install Mode. Programs installed prior to converting that...