We are in our pilot stage (30+ users) of implementing zcm in our environment. We upgraded from Zfd 6.5sp2 to ZCM (current version 10.1.3), Windows XP SP2 machines. Every couple of days or so we see computers, where no icons are in the nal window and you cannot right click on the Z icon in the systray or it will give you the error message below.

I have tried to restart the zenworks services (Novell ZENworks Agent Service, Novell ZENworks Pre Agent & Novell ZENWorks Remote Management) but that does not resolve the issue either. I have also tried a zac ref but that did not work either, the only thing that works is a reboot and then all icons appear and you can right click on Z icon and it appears healthy... Any ideas on what could cause this? For awhile I thought it was due to possible .net upgrades via wsus but it appears this happens even when wsus has not installed updates on that day.

Application Error:
The ZENworks Service does not appear to be running. Please restart the service and try your request again.