What to know about Horizon Instant Clones

Horizon 7 introduced the Instant Clone feature leverages the vmFork technology introduced in vSphere 6.0 U1. With Instant Clone technology it is possible to clone and deploy a VDI desktop VMs in seconds. This is called the Just-In-Time Desktop.

Below is an overview how an Instant Clone VM is created:

Instant Clone

  1. Master Image. The Master Image or Golden Image is a Windows 7 or 10 optimized image that contains installed software such as the Horizon Agent for example.
  2. Snapshot. A snapshot is taken of the master image.
  3. Template. Per snapshot a linked clone template is created of the master image.
  4. Replica. The replica is a full clone of the Template that is thin provisioned. The replica uses Content Based Read Cache (CBRC) and can be place on a specific datastore. This is the shared read disk for the desktop VMs.
  5. Parent. Per ESXi host a parent VM is created. The parent  is powered on. From this Parent Instant Clones are created using vmFork.
  6. Instant Clone. In a couple of seconds the the Instant Clone is created.  The Instant Clone will grow depending on the change rate but at logoff the Instant Clone is deleted and a new Instant Clone is created.

In the vCenter Server the following VM conventions are created:

  • Template: cp-template-xxx
  • Replica: cp-replica-xxx
  • Parent: cp-parent-xxxx

What to know about Instant Clones

  • vSphere 6.0 U1 or higher is needed for Instant Clones.
  • For the Instant Clone feature Horizon Enterprise or Horizon Air in Hybrid-mode is needed.
  • The Horizon View Storage Accelerator must be enabled.
  • Instant clones VMs are always powered-on.
  • Each time a user logs out of an Instant Clone, the desktop is deleted and a new desktop is provisioned and powered on.
  • The Master image must be installed with Hardware Version 11.
  • Uses ClonePrep for customization specification. All the Instant Clones uses a Single SID.
  • Parent VMs are tied to VMware ESXi host they are on and cannot be migrated or powered off through the vSphere (web) Client. This prevents an ESXi host from entering maintenance mode. Follow KB2144808 to put an ESXi host in maintenance mode.

Maintenance Mode

  • In the Horizon Agent, the Instant Clone feature must be enabled and the Composer must be disabled. It is not possible to enable both the View Composer and Instant Clone in the same Horizon Agent.
  • Instant Clones is part of the Horizon Connection Server. So no additional infrastructure component is needed. If the Horizon Connection Server fails another Horizon Connection Server takes over.
  • A Instant Clone Domain Admin is needed to add the Instant Clone to the Active Directory.
  • Deploy applications and System updates by updating the parent image and create a new snapshot. With the new push image feature you can point to the new snapshot.


What is supported:

  • Only Single-user desktops
  • Only floating pools
  • 1 vCenter Server maximum
  • 1 VLAN only
  • Windows 10 (32-64 bit) and Windows 7 SP1 (32-64 bit) as desktop Operating Systems
  • Maximum number of 2 monitors with a resolution up to 2560×1600
  • VMFS and Virtual SAN (VSAN) storage
  • Scales up to 2000 Instant Clones per pool
  • vMotion, DRS and HA

What is not supported

  • Persona Management
  • RDSH
  • 3D Graphics (NVIDIA GRID), only limited SVGA support
  • Virtual Volumes, VAAI, NFS or local datastores
  • Disposable disk
  • Dedicated pools
  • Sysprep
  • PowerCLI
  • Persistent disks. If you need persistency use for example App Volumes with a writable disk and User Environment Manager (UEM).
  • Storage vMotion of the Instant Clone


Horizon 7 includes a great new enhancement called “Instant Clones”. Within seconds VDI desktop VMs can be deployed. There is no extra infrastructure components needed such as a Composer service. With this version of Instant Clones there are some caveats you need aware off before implementing in production. Further versions of VMware Horizon will improve Instant Clones to add more support.

Horizon View Administrator displays a blank error window

After upgrading to VMware Horizon View 7, the administrator webpage displays a blank error window when trying to connect using the IP address of the Connection Server.


Horizon View 7 adds new security features that checks for the original URL for the web request. If not, it rejects the request and display the blank error window.

Steps to resolve this:

  • Use https://FQDN/admin


  • On every Connection Server create a locked.properties text file in c:\Program Files\VMware\VMware View\Server\sslgateway\conf
  • Add the following line:
    • checkOrigin=false


  • Save the file
  • Restart the “VMware Horizon View Connection Server” service

After the modification you’re able to connect to the View Administrator URL using the IP address of the Connection Server.


VMware Horizon View Client Drive Redirection

On of the new features of VMware Horizon 6 version 6.1.1 is Client Drive Redirection (CDR). Microsoft RDS and Citrix already have CDR for many years in there product. Now this handy feature is available in Horizon View. CDR is supported on VDI desktops (single-user) and RDS desktops and applications on Windows and as Tech Preview on Mac OS X clients.

Here’s a quick overview how-to enable Client Drive Redirection (CDR):


  • Horizon View 6.1.1 environment (Connection Server, composer etc.)
  • View Agent 6.1.1 or later
  • VMware Horizon Client 3.4.0 build-2769709

Install the Horizon View Agent. During the installation of the VMware Horizon Agent enable the Client Drive Redirection feature.


After installing the new Horizon View Agent is deployed on the Horizon View environment,  connect with  new 3.4.0 Horizon Client. When connecting for the first time to the there’s  a pop-up asking to access your local files. Make sure to allow this and select “Do not show this dialog again”.

View Deskstop

In the Horizon View Client there is a option called “Share Folders”. In the sharing box add local drives and folders to share in the VDI desktop session.

0_sharing Sharing

In the Windows Explorer the drives and folders that are mapped are visible.



Note: With Client Drive Redirection (CDR), the folders and files that are sent across the network are NOT encrypted!