After an experimental upgrade on some VDAs in a customer’s environment experiencing issues when connecting to our Windows 10 virtual desktops. Desktop Viewer starts up, stuck for some seconds and closes without any error or event. We just see this window:
Protokollname: Citrix-HostCore-ICA Service/Admin
Quelle: Citrix-HostCore-ICA Service
Datum: 05.10.2020 08:52:11
Benutzer: Lokaler Dienst
Citrix ICA konnte Thinwire nicht konfigurieren und zur remoten ICA-Anzeige wechseln. Das Problem kann durch einen Neustart der Arbeitsstation oder das Anmelden an der Konsole gelöst werden.
Translate from German:
Citrix ICA could not configure Thinwire and switch to the remote ICA display. Rebooting the workstation or logging in at the console will fix this.
After some minutes you just see the connection on the VM is closed due to the VDA timeout. Internal connections through Storefront are working fine all the time.
So we assumed there must be another component that is causing this issues and as we are connecting through Citrix Gateway we started to analyzing there. From Citrix Support we got the hint there are several cases regarding Session Reliability Feature on Citrix ADC and we were asked to disable it on the appliance.
To disable Session Reliability on HA failover, at the prompt, type:
set ica parameter EnableSRonHAFailover NO
Or via GUI:
After the change the connection could be established successfully and everything is working fine. To double-check we reverted the setting to enable the Session Reliability in HA and the issue came back immediately.
For now this is just a workaround and we are still working with Citrix Support to determine if there is a bug in the latest Citrix ADC firmware NS13.0 64.35.nc
Marco Klose works as a Technical Consultant and Architect focused on Application & Desktop virtualization as well as application delivery with the Citrix product portfolio. He is specialized in Citrix virtualization, Citrix networking and Microsoft products. He has +10 years experience and holds the latest Citrix certifications and is member of the Citrix Partner Expert Council EMEA (PTEC).