Mac OS X 10.4: Network Time clients lose synchronization

Some Mac OS X computers will lose time synchronization even when the "Set date & time automatically" option is selected in the Date & Time preference pane. To temporarily resolve the issue, simply deselect and then reselect that checkbox.

To permanently resolve the issue, you can modify the default values in the time synchronization configuration file. The defaults require several hours of constant access to the time server in order to establish synchronization. If the initial sync gets interrupted (by the computer going to sleep, for example), the subsequent synchronization will not take place, causing the computer to eventually drift from the correct time.

Note: Modification of the configuration file is an advanced technique. If you are not experienced in the type of steps you see below, consider using the temporary method mentioned above. The advanced steps will use the pico text editor as an example; advanced users may choose a different editor.

To modify the configuration file, follow these steps:

1. Be sure you are logged into Mac OS X with an administrator account.
2. Open the Terminal (located at /Applications/Utilities/).
3. Execute this command:
   

   sudo cp /etc/ntp.conf /etc/newntp.conf

   
   
4. When prompted, enter your administrator password.
5. Execute this command:
   

   sudo pico /etc/newntp.conf

6. Use the cursor keys lot locate the minpoll and maxpoll values, and then delete them.
7. Add "iburst" after the server address(es). Your edited file should contain an entry that looks like this:
   

   server time.apple.com iburst

   
   
8. Press Control-O followed by Return to save the file, then Control-X to exit pico.
9. Execute this command:
   

   sudo pico /System/Library/StartupItems/NetworkTime/NetworkTime

   
   
10. Change the line near the end of this file, which starts with "ntpd -f", so that it reads:
    

    ntpd -f /var/run/ntp.drift -p /var/run/ntpd.pid -c /etc/newntp.conf

    
    
11. Press Control-O followed by Return to save the file, then Control-X to exit pico.
12. To restart the Network Time service, execute this command:
    

    sudo SystemStarter -d restart "Network Time"

    
    

Note: These changes will help Mac OS X establish time synchronization quickly. Time drift may still occur if the computer's network configuration changes. To re-establish synchronization, restart the Network Time service as described in the last step above.