The ProxySG appliance becomes unresponsive and must be restarted when there is a heavy traffic load.
The most common cause of this problem is setting too high of a value for the Maximum number of connections for the ICAP service. With too high of a value, ICAP connections start queuing up, and eventually the ProxySG appliance will run out of memory and need to be restarted. When editing the ICAP service, you should use the Sense settings button to have the ProxySG appliance retrieve the appropriate setting from Content Analysis.
To check these settings, go to Configuration > Content Analysis > ICAP > Edit.