There is a specific process that should be followed when updating the Windows Operating System (OS) on a Virtual Disk (vDisk) when using Citrix Provisioning Services (PVS) Imaging Wizard. Some Customers will run into issues, and this article sets forth the proper expectations and process to ensure success when performing a Windows OS vDisk upgrade.

Instructions

1. If there are Network driver updates please make sure to reverse Image the Vdisk first to allow VM to boot from local disk: How to Perform Reverse Imaging on a Provisioning Services Target Device for Windows and its Applicable Usages (citrix.com)
2. Upgrade the Operating System on the Hypervisor/Physical Machine
3. Uninstall the Citrix Provisioning Target Device Agent Software
4. Restart the Machine
5. Reinstall the Provisioning Target Device Agent Software
6. Once the reinstall completes, the Provisioning Services Imaging Wizard will start automatically, to create a vDisk
7. Once the vDisk is completed, the Imaging Wizard will request another reboot
8. Once the machine has completed the reboot process, the Imaging Wizard will automatically start the harddrive to vDisk copy

Note 1: Recommended that when the Operating System (OS) upgrade completes, all Citrix Software (including the Citrix Virtual Delivery Agent (VDA) software, the Citrix Provisioning Services (PVS) Target Device Agent software and Workspace App software) should be uninstalled and reinstalled/reseated into the OS. This is recommended due to the nature of the OS Upgrades, and the different DLL files and binaries that change between versions that may overwrite the Microsoft Registry items as well as some of the DLL registrations. 

Note 2: It is not recommended or best practices to upgrade the Operating System and not uninstall the Citrix Provisioning Services Target Device Agent software. When the Target Device Agent software is not uninstalled and reinstalled onto the machine after undergoing an OS upgrade, the harddrive to vDisk process will fail. This will cause the vDisk not to create properly, and the Target Devices will be unable to boot.