Military Time - Tahoe 26.6.2

1Writer wrote:

Why is my military time not showing in all accross my Mac? When I turn on my Mac it doesn't show military time.

The setting to enable 24-hr time is in System Settings > General > Date & Time:

However, your question implies something slightly different. "When I turn on my Mac..." suggests that your Mac is showing 24-hr time during normal use but not on the login screen when you boot up your Mac.

If that's the case, then that is expected behavior and it may have changed for you between Sequoia and Tahoe. The reason is that Tahoe has FileVault enabled by default. All Macs that can run Tahoe have the internal storage encrypted at the hardware level. FileVault increases security by incorporating the user's login password into the cryptographic key. Practically, that means that after a reboot/startup and before you enter your login password, the Mac is not able to access user account settings or the internet.

When FileVault is enabled, a Mac boots by stopping at an early pre-boot authentication screen to decrypt the startup disk before loading the main operating system or network services.

Changes to the boot sequence with FileVault enabled:

• Early Password Prompt: You see a special FileVault unlock screen immediately after the hardware loads, before normal user services or Wi-Fi connections start.
• No Network Access Yet: Because network stacks require user-space services to run, the Mac cannot connect to standard Wi-Fi networks until you enter your password to unlock the drive.
• Decryption Unlocks the OS: Entering your account password provides the key to decrypt the drive, allowing the Mac to hand off control and finish booting into the standard macOS interface

You can disable FileVault in System Settings > Privacy & Security > FileVault (near the bottom of the settings pane) – click the setting and toggle FileVault off.

With FileVault off, the boot sequence will be 'normal' because user settings and network access will be available prior to entering the login password. Keep in mind that Apple enabled FileVault by default with the upgrade to macOS 26 Tahoe for a good reason – to protect your Mac. If someone gains physical access to your Mac and you do not have FileVault enabled, it is a simple matter for them to access the data stored on your internal drive, either by changing your login password or via the Recovery OS. With FileVault enabled, your login password is required to access your internal storage.

There is no 'overhead' in using FileVault. Implementations on older Macs (none of which are capable of running Tahoe) used software-based encryption and decrypted data 'on-the-fly', meaning it could take hours to enable or disable FileVault and there was additional processor load with it on. Modern Macs (with Apple Silicon or the last rounds of Intel Macs with the T2 Security Chip) perform encryption/decryption with dedicated hardware that is active regardless of whether or not FileVault is enabled – turning it on just changes the cryptographic key stored in the Secure Enclave.

More info on FileVault:

Protect data on your Mac with FileVault – Apple Support

Intro to FileVault – Apple Support

24-hour time

Use a 24-hour format for the time shown in the menu bar. For example, instead of 3:00 pm, show 15:00.

To change these settings, choose Apple menu 

 > System Settings, click General  in the sidebar,

then click Date & Time. (You may need to scroll down.)

There was (is?) a settings-related bug potentially lurking here in at least some recent macOS versions.

Details of some of the settings shuffling that reportedly got to 24 hour on their lock screens:

https://apple.stackexchange.com/questions/465610/how-do-i-display-a-24-hour-clock-on-my-mac-login-screen#465614

This including the reply posted by user “Piet Thijssen” there, indicting that changing their main language away and then back again might be necessary.

What has been said about using the 24 hour clock. And military time as I was introduced to it decades ago was based on that clock. However, current military time, to play nice with NATO, is a different animal and not used by macOS.

Chattanoogan wrote:

Another interesting “nugget” you are always so adept at “digging up.” 🫡

Gracias.

I’m taking my M5 MBP out to the PDT time zone this weekend; will see how this particular piece behaves.

The macOS 26 boxes reboot so infrequently, I just don't get to look at the lock screen all that often.

There's been what seems to be a very rare iCloud preferences-related caching bug with some settings, too.

Setting shows as (whatever) but doesn't work as (whatever), so toggling the setting to the unwanted value, force-restarting or safe-mode restart, and re-selecting the (whatever) setting usually resolves that.

That caching corruption may well have been fixed too, but it's been so transient that I'd not know when or if.

But that caching bug manifests very differently from this particular lock screen time display (mis)behavior.

PS: to clarify some comments about macOS 26 upgrades and defaults mentioned earlier, FileVault isn't enabled by default on all macOS 26 boxes. This having just checked a recently-migrate-upgraded Mac. Internal storage hardware encryption is enabled, but FileVault is (still) off. The existing FileVault setting was preserved during the migration-upgrade process.

Thanks.

This particular MBP’s File Vault is DEF on.

It was activated during the “just out of the box” startup; there was no migrating involved.

(This particular MBP is starting it’s life as a “blank sheet” — any any apps and files are only being added as-needed)

Will double-check and record all pertinent time-and-date relevant settings prior to travel.

I wish I had something more helpful to add, but when I’m logged in as me — a “standard” user — and changed my Time Zone City to PDT, the login screen changed too (as expected). Even after a power-off shutdown.

It did prompt me for administrator account credentials to make the change, but that seemed normal and was required of previous MacOSs on previous hardware. .

So, from a cold start boot-up, my “select user / login” screen displayed the PDT I had set.

Upon return, the reverse worked as expected too, with all clocks now displaying EDT; even before ANY user initially logs in after a cold power-up bootup.

And again File Vault IS enabled and I’m running MacOS 27.0 on an M5 MBP.

Of note, this MBP is being manually “built up.”

Meaning that there was no “Apple migration” from my prior MBP; so nearly all settings are still at “default” — unless there was a good reason to make an alteration.

Whether this is significant factor here is unknown.

Thank you. 😊

I thought I was the only one “sensitive” to the conflation of 24-Hr Time (e.g. 07:25) with Military Time (e.g. 0725Q)

only ever heard 24hour (which is default where I live, we have no AM / PM versions really) being referred to as military time in USA.

I pay no attention to the current military time manipulation by longitude and alpha letter suffix. I still think in terms of the venerable 24-hour clock.

Another interesting “nugget” you are always so adept at “digging up.” 🫡

I’m taking my M5 MBP out to the PDT time zone this weekend; will see how this particular piece behaves.