The cache disk on a Citrix PVS target fills and a server that is attached to it crashes.

Symptoms

Above normal CPU utilitization by the DAgentUI.exe process(es).
The per-user log, DAgentUI{USERNAME}{PID}.log, contains the following entries, repeatedly:

[MM/DD/YYYY hh:mm:s.ms TID #] DAgentProxy.cpp:518 CDAgentProxy::WaitForDAgentService() Waiting 15000 ms for DAgent service
[MM/DD/YYYY hh:mm:s.ms TID #] DAgentProxy.cpp:546 CDAgentProxy::WaitForDAgentService() Wait returned - -1
[MM/DD/YYYY hh:mm:s.ms TID #] DAgentProxy.cpp:362 CDAgentProxy::WaitForDAgentData() entered
[MM/DD/YYYY hh:mm:s.ms TID #] HideTrayIconThread.cpp:37 CHideTrayIconThread::HideClientTrayIcon() entered
[MM/DD/YYYY hh:mm:s.ms TID #] HideTrayIconThread.cpp:51 Destroying tray icon

Cause

The Altiris Deployment Agent service is not running or has been disabled. This causes the per-user log to fill with events and subsequently fill the cache disk. 

Solution

If the service MUST be disabled, delete the DAgentUI registry value in the registry that starts the per-user process (DAgentUI.exe).

Otherwise, start the Altiris Deployment Agent service.