macOS - ntpd uses more than 100% of CPU

it happens couple times every day, my MacBook becomes extremely slow. When I check Activity Monitor, I see that ntpd process uses more than 100% of my CPU (usually around 140-180%).

If I kill it (Force Quit), MacBook starts working as usual. But it will happen again in several hours. How can I fix this issue? It becomes really annoying

It started after one of the software updates (not sure exactly when).

MacBook Pro (Retina, 13-inch, Late 2013) with macOS 10.12.3

Solution 1:

Go to System Preferences > Date and Time and uncheck Set date and time automatically. Close System Preferences, then reopen and re-check Set date and time automatically

Solution 2:

Check if the NTP servers you have configured are correct and reachable.

Open a Terminal window and run

ntpq -p

This is the output I got on my system which had ntpd using around 80-90% cpu.

     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
*aer-foo5d20-dc- .GPS.            1 u   23   64   17   17.888   20.617   2.226
 aer-foo6t20-dc- .GPS.            1 u   23   64   17   17.938   20.598   2.211
 defra1-ntp-001. .INIT.          16 u    -  68m    0    0.000    0.000   0.000

This shows that I had 3 ntp server configured, the 2 first ones are ok but the 3rd one was unreachable (I'm no NTP expert but refid=.INIT., st=16 and reach=0 all seem to indicate something is wrong).

So I went to System Preferences > Date and Time , where indeed I had 3 ntp servers configured: 2 inside my company's network, and time.apple.com - so nothing resembling "defra1-ntp-001". Assuming "defra1-ntp-001" referred to time.apple.com I removed that one, and this resolved my problem.

Of course in my specific case, probably time.apple.com was unreachable because it is blocked by my company's firewall, so I don't recommend removing it as a general solution. Instead check your 'ntpq -p' output and try to determine which server is causing the problem and remove that one (and if none are left, add a known good one).