Unstable Wi-Fi connection after wake from sleep when NS is running

I installed the latest Norton Security for Mac on my 2011 MBA (running Yosemite, with all updates installed), completed all NS live updates. Ever since, my MBA won't maintain the wi-fi connection after coming out of sleep mode. My Mac will connect to my home's router, but than after 5 to 7 seconds, the connection is dropped and the Mac tries to reconnect and it fails. I can manually turn off Wi-Fi then turn it on and it will drop again after 5-7 seconds. I can repeat this 5 or more times with the same result. I can never acquire a stable connection until I reboot. After reboot, I get a clean connection that does not disconnect.

I have also verified that when this fails, I can open NS, select the Advanced tab, select Firewall, then turn off Connection Blocking and Vulnerability Protection temporarily, then establish a Wi-Fi connection, then enable the firewall features and the connection is stable - avoiding the need to reboot.