Had to Uninstall Norton!

I finally had to uninstall Norton from my Macs because it broke FTP connections and caused massive system instability (KP crashes); breaking my FTP apps (started today) was the last straw.  The massive system instability (KP crashes) began ever since installing Yosemite.  I purchased Norton One and installed on all my machines; Windows and Mac.  I'm now not using any AV on the Macs because of this bug laden software you have provided; please provide me some assistance.