When you attempt to shadow session from Director there is an error displayed: Shadow Session Failure - Remote Assistance failed to start.
When Admin tries to use MSRA it also fails with the error: Your offer to help could not be sent

Event logs on the VDA displays the errors:

Application Log: 
Event 1000
Faulting application name: RAServer.exe

Microsoft-Windows-CodeIntegrity/Operational:
Event 3033
Code Integrity determined that a process (\Device\HarddiskVolume3\Windows\System32\raserver.exe) attempted to load \Device\HarddiskVolume3\Program Files\Citrix\HDX\bin\ParseAndValidatePath.dll that did not meet the Microsoft signing level requirements.


 

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.

Please contact Citrix Technical Support and request an updated binary. You can reference the issue number: CVADHELP-20980

Possible workarounds:

1 -  Exclude RAserver.exe from Shell Hook

Open registry editor on the VDA and go to:
Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Citrix\CtxHook\AppInit_DLLs\Shell Hook
Edit value: 'Exclude'  REG_MULTI_SZ 
Add RAserver.exe to the Exclusion list.
Reboot VDA.

2 - Exclude RAserver.exe from all Citrix hooks:
Open registry editor on the VDA and go to:
Computer\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\CtxUvi 
Edit value: UviProcessExcludes and add RAserver.exe to the list of excluded processes.
Reboot VDA.

Note: Do not push these registry changes using group policy, as this may disable the CtxUvi driver on the VDA causing the users to get a Grey screen on launching a session until the VDA is rebooted. 

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Problem Cause

When the RAServer process starts, Citrix Shell Hook is loaded. It attempts to load another library: ParseAndValidatePath.dll.
DLL Signature does not meet signing level requirement. 

 

Citrix API Hooks: https://support.citrix.com/article/CTX107825/how-to-disable-citrix-api-hooks-on-a-perapplication-basis