Problem: The Application Virtualisation Client could not launch X
An unexpected error occured. Report the following error code to your System Administrator.
Error Code: 4604EE8-0B017604-0000040F

Solution:

1. Delete the clients (users) cache for AppV for the application
2. Check the applications .pkg file on the local share of the server is definitely the latest version of the package. (in our instance the package had been updated but this was not reflected on the local cache of the server – ever after a reinstall of the AppV MSI) Remove the AppV App and its local .pkg file from the server and reinstall