How FTA’s (File Type Associations) Work in MED-V V2

One of the most major feedback items about MED-V V1 was the lack of FTA (file type association) linkage between host documents and guest applications. This changed in MED-V V2. Through the use of RDP-redirected folders and the RemoteApp-style of FTA configuration, you are able to take advantage of this so long as the applications are published properly to the host (Windows 7) and the application maintains those associations in the guest operating system (Windows XP.) This only works in one direction (host documents to guest applications.)

Host Operation

MED-V FTA overrides are user-based and are registered to HKEY_CURRENT_USER. For example, if you have an application called “Application A” with an executable of Application1.exe, and it registers an extension – .ABC, there will be a registration for the FTA located in HKEY_CURRENT_USER\Software\Classes\.ABC

The default value will be REG_SZ-based in the form of <PAI><VMName> where the PAI will be the hash of the published application and separated by dots will be the name of the virtual machine hosting the application (with spaces replaced with periods “.” If present in the VMName field.) So if you have a published application in the virtual machine called “Windows XP Compatibility” it would look something like this:


There will be a subkey HKEY_CLASSES_ROOT\.abc\OpenWithProgids tying to this same special object. In addition, you will see a registration for this file type object by its name (6abd1cee.Windows.XP.Compatibility) also registered in HKEY_CURRENT_USER with a \shell\open\command sub key that
contains the path to open the published application. Using the above example, it would like this:

“C:\Program Files\Microsoft Enterprise Desktop Virtualization\medvhost” /launchapp “Windows XP Compatibility” “||6abd1cee” “Application A” “%1”

In the screen shot below, you will see a series of examples using Visio 2002 as the published application registering its file type associations in the host.


Guest Operations

The application will launch and load the file from the host operating system using RDP folder redirection (i.e. \\TSCLIENT\C\Users\<USERNAME>\Desktop, if clicking on the host desktop.) You will not expect this seamless behavior when running the application from a VPC window (a full desktop) because it is
out of band to MED-V and the MED-V agents cannot automatically redirect using the RDP folder redirection mechanism. The only File Type Associations that will automatically publish will be those associations in the guest operating system belonging to applications that are auto-published.


Conflicts may occur if the published application shares a file type with one installed in the guest. From my experience it will only be a concern if you are desiring the use of the local application in place of the published application.

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