Why wont My Mac Let me change the date and time?

Rarely, Mac users may notice their clock is displaying the wrong system time. This typically occurs after a Mac has been shut down for an extended amount of time and hasn’t connected to the internet in a while, but it can also happen with traveling across date lines, between regions with daylight savings time observations, and in other situations as well.

While having the clock off may not sound like a big deal, it can lead to all sorts of frustrating issues, from some apps not working, to an inability to install OS X due to verification errors, to “connection not private” errors in web browsers, to a variety of other nuisances.

Fortunately, fixing the Mac clock if it’s showing an incorrect time is quite simple, as we’ll demonstrate in this walkthrough.

How to Fix an Incorrect Time Displaying in Mac OS X

Be sure the Mac is connected to a wi-fi network or ethernet network, this is necessary to access the internet time servers and maintain a consistently accurate date and time on the Mac clock.

1. Go to the  Apple menu and choose ‘System Preferences’
2. Select the “Date & Time” control panel
3. Choose the “Date & Time” tab and check the box for “Set date and time automatically:” – optionally, choose a different time server to use, but the Apple time server time.apple.com is highly accurate and this is really not necessary unless the detected region is wrong

4. Now choose the “Time Zone” tab and check the box next to “Set time zone automatically using current location” – this will use location services to determine where the Mac is located so that the date and time are consistently updated automatically, even if the computer moves across time zones

5. Double-check the time is correctly showing in the upper-right corner menu bar clock and in the “Clock” preference panel, and exit out of System Preferences when finished

That is by far the simplest approach to guaranteeing the Mac consistently shows the proper time in the clock and uses the proper date and time with applications. This is the recommended approach, particularly for Mac users who travel or who leave their computers off for an extended period of time, as the latest region and time is pulled automatically from Apple servers to set the proper clock and date information.

Option 2: Manually Setting the Mac Clock, Date, Time, Time Zone

For users who do not want to enable location services, in situations where the Mac is not accessing the internet, or for whatever reason just don’t want to use the recommended automatic time detection settings (maybe you’re building a time machine? How exciting), you can also manually set the clock and date and time yourself in Mac OS X. This is done through the same preference panel:
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There’s nothing inherently wrong with setting the date and time yourself on a Mac, but if you change locations, if the computer has been off for an extended period, or maybe the Mac was sent into orbit for a while or out elsewhere into space and experienced the effects of special relativity, you may see the clocks are off as a result. Thus, it’s best to use the automatic settings in Mac OS X to determine location and set the time appropriately via Apple’s time servers.

Why is the Mac showing the wrong time? Why is the clock off?

The most common reasons for Macs to display the wrong time are:

• The Mac has been turned off for an extended period of time
• The Mac is older and the onboard battery has died, thereby necessitating manual clock setting or proper time serving from the internet
• The clock or time zone in Mac OS X was inadvertently changed
• The Mac changed time zones (say, a MacBook traveling overseas) and the computer did not update the date and time for the new location
• Location services are disabled on the Mac, as is automatic time server setting
• The Mac functioned as a satellite, traveled into orbit, hung around on ISS for a while, or spent time in deep space and has now experienced special relativity and or time dilation – this is perhaps less likely unless you’re an astronaut or a rocket scientist, but hey it’s possible!

Of course there are other possible situations where a clock can go awry as well, but these are the most common reasons you’ll see the clock off on a Mac. If you encountered these issues after coming back from an extended break or after traveling across the date line or into a new time zone, you may also discover your iOS devices are off as well, but fortunately fixing an iPhone or iPad showing the wrong time is easy too.

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