Symantec Endpoint Protection (SEP) 14.3 RU2 hangs on the initial opening of the client interface. This happens if the IPS Policy has multiple IPS Signature Exceptions set to Allow. Once the client is able to load, it can be closed and opened again without issue. A restart of the SMC service or a reboot causes the issue to come back again.
SEP 14.3 RU2
A large amount of IPS Signature Exceptions.
This issue is fixed in Symantec Endpoint Protection 14.3 RU3 and 14.3 RU2 P1. For information on how to obtain the latest build of Symantec Endpoint Protection, see Download the latest version of Symantec Endpoint Protection.