OS X Settings, Lock Screen duration limited to one hour

Give this a try: boot into Safe Mode according to How to use safe mode on your Mac and test to see if the problem persists. Reboot normally and test again.

NOTE 1: Safe Mode boot can take up to 3 - 5 minutes as it's doing the following; 

• 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

NOTE 2: 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.

ctlow wrote:

In Settings -> Lock Screen, I cannot adjust "Require password after screen saver begins or display is turned off" beyond one hour.

Here at "HQ", with two Minis, the 2018 works fine. It's only an issue on the 2020 (M1).

Not serious, just a nuisance; I want a longer duration.

Have rebooted, have rebooted into an Admin account (it works there), but in the non-Admin account, it asks for Admin-credentials, and then I set four hours and it stays at one hour.

???

(OS X completely up to date.)

Thanks in advance.

The current stable release of Ventura including bug fixes, security updates is macOS Ventura 13.1

Keep your Mac up to date - Apple Support

Keep your Mac up to date - Apple Support

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