After seeing slow boot ups and lots of ntp traffic on boot up of Mint, I did some digging. Mint installs with a pile of ubuntu ntp servers defined in /etc/ntp.conf. When using a NAT virtual connection, the VM does not see any local time servers (like my router). The network traffic to synchronize time with those servers flows even if Parallels is set to use the host Mac time. I commented out all the ubuntu stuff and added in time.apple.com. Seems to limit network traffic and still gives the correct time. Does anyone have a suggested way to force the use of just the Mac clock and shoot ntp in the head on Mint? It seems to be intertwined with the whole system startup mess that is now Linux.