macOS Sequoia menubar clock 24-hour format not working

Dvitto wrote:

No, I have not tried the reboot into safe mode.

It sounds like a hail Mary to me ^^!

Acutally it can fix a lot of strange system performance problems. It's doing the following during boot:

• Verifies your startup disk and attempts to repair directory issues, if needed

• Loads only required kernel extensions (prevents 3rd party kernel/extensions from loading)

• Prevents Startup Items and Login Items from opening automatically

• Disables user-installed fonts 

• Deletes font caches, kernel cache, and other system cache files

In deleting the various caches it will remove some that might have been damaged or corrupted and, thus, cause unexpected system performance.

NOTE if you have a wireless keyboard with rechargeable batteries connect it with its charging cable before booting into Safe Mode. This makes it act as a wired keyboard as will insure a successful boot into Safe Mode.

So boot into Safe Mode, change the time format and reboot normally. See if that makes any difference.

I noticed this just now and went to system setting general date and time AND also control centre - menu bar only. Basically just moved all sliders to 'off' even if they were set as I wanted. Then sliding on the required ones found I could click on the time and enter the correct numbers - seems to work. I have restarted and it 'holds' I even put fancy seconds to drive me nuts. Hope this works for you and others who are puzzled.

This is my desired setting...

Reboot in safe mode worked for me, I also had this 12/24 Date/Time bug.

FWIW, I see the same behavior.

You can send a bug report from the feedback page.

Feedback - macOS - Apple

Just a theory. The clock may not switch from 12hr to 24hr time until the top of the hour. Mine switched when it went from 12:** to 1:00.

For the heck of it, have you tried rebooting into safemode then back again to test it out?

Start up your Mac in safe mode - Apple Support

Also there's this info for reference in case you hadn't already seen it:

Change the menu bar clock format on Mac - Apple Support

Hmmm. After playing with the settings a couple times it finally switched to 24 hour time. Beats me.

Dvitto wrote:

How did you do it?

Also, about your theory, if it switched from 12:XX into 1:XX you are still seeing the same 12-hour format AFAIU

It should have been 13:00 unless you mean it was after midnight.

I guess I didn't explain it well. It went from 12:** PM to 13:00 at 1:00 PM.

In your example image:

it appears that the menu bar time may be set to 24 hr time.

I've noted for over a year (since Ventura) that in the menu bar time display is set to 24 hr time, in a four digit format, the leading ZERO is not displayed.

but a non-zero first digit is displayed correctly:

Is that what you are seeing?

Flipping that switch in settings immediately adds or drops the AM/PM from the toolbar display here.

BDAqua wrote:

Flipping that switch in settings immediately adds or drops the AM/PM from the toolbar display here.

That's not the issue. The issue is switching from 12hr time to 24hr time.