If non of the above suggestion not helps try this
adjust the Symantec Endpoint Protection Manager heap size:
Click Start> Run.
In the Run dialog box, type regedit
Press Enter.
Locate the following registry key:
HKLM\SYSTEM\CurrentControlSet\Services\semsrv\Parameters\
Locate the following keys:
JVM Option Number 0
JVM Option Number 1
Adjust the key values upward, and for optimal performance, match the key values.
For example, to create a 1 GB static heap, set: "JVM Option Number 0" to "-Xms512m", and set "JVM Option Number 1" to "-Xmx1024m".
Close Regedit.
Click Start> Settings> Control Panel> Administrative Tools
In the Services dialog box, right-click Symantec Endpoint Protection Manager, and then click Restart.