The connected session is suddenly disconnected. The client side event log records the error message as below.

"The description for Event ID 1 from source ICA Client (Vanadium) cannot be found. Either the component that raises this event is not installed on your local computer or the installation is corrupted. You can install or repair the component on the local computer.

If the event originated on another computer, the display information had to be saved with the event.

The following information was included with the event: 

Vanadium: TW Protocol error: Data rejected

Caution! Using Registry Editor incorrectly can cause serious problems that might require you to reinstall your operating system. Citrix cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk. Be sure to back up the registry before you edit it.

In Citrix Receiver 4.9 LSTR, the fix of LC7655 introduced 2 registry key Tw2IgnoreValidationErrors and Tw2IgnoreExecutionErrors. If the ICA Client (Vanadium) error happened, we can try to use the following registry settings to resolve the problem.

On 32-bit Windows:
---------------------------
HKEY_LOCAL_MACHINE\SOFTWARE\Citrix\ICA Client\Engine\Configuration\Advanced\Modules\Thinwire3.0
Name: Tw2IgnoreValidationErrors
Type: REG_SZ
Value: TRUE

HKEY_LOCAL_MACHINE\SOFTWARE\Citrix\ICA Client\Engine\Configuration\Advanced\Modules\Thinwire3.0
Name: Tw2IgnoreExecutionErrors
Type: REG_SZ
Value: TRUE
---------------------------

On 64-bit Windows
---------------------------
HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Citrix\ICA Client\Engine\Configuration\Advanced\Modules\Thinwire3.0
Name: Tw2IgnoreValidationErrors
Type: REG_SZ
Value: TRUE

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Citrix\ICA Client\Engine\Configuration\Advanced\Modules\Thinwire3.0
Name: Tw2IgnoreExecutionErrors
Type: REG_SZ
Value: TRUE
---------------------------
 

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Problem Cause

After get the graphic data packet from VDA server, Windows Receiver will validate the received data packet. Sometimes due to network stability or some other reasons the data packet is invalid. It will cause the client side validation failed. The default process is to disconnect the session if client side get the invalid graphic data packet. After set Tw2IgnoreValidationErrors and Tw2IgnoreExecutionErrors to TRUE, client will ignore the invalid data packet and go on the next data packet processing, so the session will not be disconnected.