I believe the solution is to migrate up to 11.0.6200 (RU6 MP2):
"CCApp is trying to close" dialog no longer appears on shutdown
Fix ID: 2077858
Symptom: Under a high workload while a computer is shutting down, occasionally the dialog box "CCApp is trying to close" appears.
Solution: Code changes to ensure the shutdown signal is correctly received and processed by all application processes that are running.
sandra