Daily clock drift of several minutes

Solution 1:

Looks like some special characters got inserted at the end (especially the 0x2e part which represents a simple .) and OS X now interpretes this as part of the server name. To fix, just run

sudo echo server time.apple.com > /etc/ntp.conf
sudo chown root:wheel /etc/ntp.conf

from the Terminal.

As to why you have this issue I have no clue.

Solution 2:

Since I (experimentally) made the following change, I've ceased to have clock drift issues, despite by /etc/ntp.conf file's contents not technically changing:

Open the Date & Time settings dialog, change the time server from Apple Americas/U.S. (time.apple.com) to Apple Asia (time.asia.apple.com) and then back to Apple Americas/U.S. (time.apple.com). From there, my daily time drift has ceased to occur.

This is a rather unsatisfying answer -- I'd love to change the select answer if anyone comes up with the real, underlying cause.