Norton Internet Security for Mac forces Restart on Yosemite

Since upgrading my OS to Yosemite, I've noticed random computer restarts. Sometimes there is a message and report available (each with a different process active at the time), and other times there is nothing. When I uninstalled Norton, the problem goes away. I did a fresh install of Norton, and it returns. There is an apparent incompatibility with Yosemite, possibly related to multiple user accounts. I really need a solution to this ASAP!

Computer: iMac (mid-2011); Intel Core i7 (3.4 GHz), 32 GB RAM

OS Version: Yosemite, 10.10.2