Users cannot log off from a XenApp 6.5 ICA session and the “Waiting for System Event Notification Service” pop-up is displayed.
- Windows Server 2008 R2
- Citrix XenApp 6.5
- Office Communicator 2007 R2
The screen remains unresponsive with the “Waiting for System Event Notification Service” pop-up. On the server user has a Communicator (OCS) running and one of the instances is pegging an entire core resulting in users unable to log off sessions.
As a workaround you can do the following: To log off successfully from the unresponsive sessions, terminate the pegged OCS process. For a permanent solution you need to apply this fix from Microsoft Cumulative update package for Office Communicator 2007 R2: December 2012.
Original post at the Citrix knowledgebase.