To upgrade the Agent in a Citrix VDI environment:
Install the latest agent on the base machine.
Go to %ZENWORKS_HOME%\conf and delete the DeviceData and DeviceGUID files.
Clear ISD (Image Safe Data) by using %ZENWORKS_HOME%\bin\preboot\ziswin.exe
Shutdown the device and take a snapshot.
In the Citrix Studio, go to Machine Catalog and click Update Machines.
Select the latest snapshot that was taken in Step 4, and then complete the on screen instructions.