Horizon View: USB Redirection Problems


USB redirection in View Client fails to make local devices available on the remote desktop, or some devices do not appear to be available for redirection in View Client.


  • The following are possible causes for USB redirection failing to function correctly or as expected.
  • USB redirection is not supported for Windows 2003 or Windows 2008 systems or for View desktops that are managed by Microsoft Terminal Services.
  • Webcams are not supported for redirection.
  • The redirection of USB audio devices depends on the state of the network and is not reliable. Some devices require a high data throughput even when they are idle.
  • USB redirection is not supported for boot devices. If you run View Client on a Windows system that boots from a USB device, and you redirect this device to the remote desktop, the local operating system might become unresponsive or unusable. See http://kb.vmware.com/kb/1021409.
  • By default, View Client for Windows does not allow you to select Human Interface Devices (HIDs) and Bluetooth devices that are paired with an HID for redirection. See http://kb.vmware.com/kb/1011600.
  • RDP does not support the redirection of USB HIDs for the console session, or of smart card readers. See http://kb.vmware.com/kb/1011600.
  • RDP can cause unexpected problems when using USB flash cards. See http://kb.vmware.com/kb/1019547.
  • Windows Mobile Device Center can prevent the redirection of USB devices for RDP sessions. See http://kb.vmware.com/kb/1019205.
  • For some USB HIDs, you must configure the virtual machine to update the position of the mouse pointer. See http://kb.vmware.com/kb/1022076.
  • Some audio devices might require changes to policy settings or to registry settings. See http://kb.vmware.com/kb/1023868.
  • Network latency can cause slow device interaction or cause applications to appear frozen because they are designed to interact with local devices. Very large USB disk drives might take several minutes to appear in Windows Explorer.
  • USB flash cards formatted with the FAT32 file system are slow to load. See http://kb.vmware.com/kb/1022836.
  • A process or service on the local system opened the device before you connected to the remote desktop.
  • A redirected USB device stops working if you reconnect a desktop session even if the desktop shows that the device is available.
  • USB redirection is disabled in View Administrator.
  • Missing or disabled USB redirection drivers on the guest.
  • Missing or disabled USB redirection drivers or missing or disabled drivers for the device that is being redirected on the client.


  • If a redirected device remains unavailable or stops working after a temporary disconnection, remove the device, plug it in again, and retry the redirection.
  • In View Administrator, go to Policies > Global Policies, and verify that USB access is set to Allow under View Policies.
  • Examine the log on the guest for entries of class wssm_usb, and the log on the client for entries of class wswc_usb.
  • Entries with these classes are written to the logs if a user is not an administrator, or if the USB redirection drivers are not installed or are not working.
  • Open the Device Manager on the guest, expand Universal Serial Bus controllers, and reinstall the VMware View Virtual USB Device Manager and VMware View Virtual USB Hub drivers if these drivers are missing or re-enable them if they are disabled.
  • Open the Device Manager on the client, expand Universal Serial Bus controllers, and reinstall the VMware View Generic USB Device driver and the USB driver for the redirected device if these drivers are missing or re-enable them if they are disabled.

The View virtual machine is not accessible and the View Administration console shows the virtual machine status as “Already Used”


If a desktop that is set to refresh or delete after log off is reset, the desktop goes into the Already Used state, or possibly the Agent Disabled state.

This security feature prevents any previous session data from being available during the next log in, but leaves the data intact to enable administrators to access the desktop and retrieve lost data or investigate the root cause of the reset. Administrators can then refresh or delete the desktop.

The View desktop can also go into the Already Used state if a virtual machine is powered on in another ESXi host in the cluster in response to an HA event, or if it was shut down without reporting to the broker that the user had logged out.



To resolve this issue, perform a refresh of the desktop using the View Administration console. For more information, see the VMware Horizon View Administration guide relevant to your version.

Alternatively, In View 5.1.2 and later releases, you can add a View LDAP attribute, pae-DirtyVMPolicy under OU=Server Groups, DC=vdi, DC=vmware, DC=int, and set the values below for the attribute.


The pae-DirtyVMPolicy values provide these options for the Refresh on logoff policy:

  • pae-DirtyVMPolicy=0: Mark virtual machines that were not cleanly logged off as Already used and block user access to them. This is the default behavior in View 4.6 and later releases.
  • pae-DirtyVMPolicy=1: Allow virtual machines that were not cleanly logged off to become available without being refreshed. View Client users can access these desktops.
  • pae-DirtyVMPolicy=2: Automatically refresh virtual machines that were not cleanly logged off. View Client users can access these desktops after the refresh operation is completed

Coming October 12 to CloudCredibility.com:…

CloudCred: VCP6-NV Exam Prep Task Series – Part… | VMware Communities

Coming October 12 to CloudCredibility.com:…

CloudCred announces the first half of the VCP6-NV Exam Preparation Task Series! 110 NV-EXAM tasks will be available on October 12 at #CloudCred, covering the first four of nine sections outlined in the VCP-NV Exam Blueprint version 1.2.

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