(1) SysDaemon chewing 200% CPU requiring me to kill the process or risk the fan deafening me, and the computer ending up as a Macbook Puddle of aluminium
(2) continuous spurious firewall messages about "applications" trying to access the internet - the programs in question - text files, .jpg files. No, I don't have a virus.
(3) repeated warnings about applications (e.g. Chrome, Dropbox, Google Music Manager, Drobo Dashboard) trying to access the internet, even after I select to allow the activity and not be warned about it again.
I have tried a complete uninstall and reinstall - the problems persist.
I can only conclude that Norton Security is not compatible with El Capitan.
Chats with Norton technical support have been not particularly enlightening.
I have Norton Security (7b124) installed on my Macbook Pro (El Capitan 10.11.2 - beta5 of .2 release from AppleSeed).
I have had these problems even with vanilla El Capitan