Time not right after restart

[supanatral]

my computer use to have a problem that even though the "set date & time automatically" was selected, it was wrong so i unchecked it and picked the time manually but every time that i restart my computer the time changes to 5 hours behind the correct time. I have the right time zone selected and i'm wondering what could cause that?

P.S. It works now (about 2 months later) if I select the "set date & time automatically" but i'm just wondering for curiosity sake.

 

[darrell888]

When you enable the "set date & time automatically" and specify a Network Time Protocol Server, e.g. time.apple.com, you are actually just enabling NTP (Network Time Protocol). If you go to a Terminal and enter the following:

ps -ef | grep ntpd

you should see the Network Time Protocol Daemon (ntpd) running. What is basically happening is the ntpd is occasionally contacting the machine specified, e.g. time.apple.com, and asking it to synchronize your time and date with the time and date on that other machine.

If the other machine's time and date are wrong, your time and date will be wrong.

If you don't have a connection to the other machine, the clock on your computer can drift.

The only other thing I can think of is if you are in the Eastern Standard Time (EST) zone and have the wrong International settings, you could be displaying GMT (Greenwich Mean Time) which is 5 hours different from EST.