Newly Created User Doesn't Appear ... Anywhere

Maybe the user accounts are being hidden. Run the following command from the Terminal app to see if the "IsHidden" flag has been set and whether it is marked as "hidden":

sudo  dscl  .   read   /Users/<name-user-account>  IsHidden  

Replace "<name-user-account>" with the actual short user name for the account you created.

You can set or reset the "hidden" option using these instructions:

https://support.apple.com/en-us/HT203998

sudo  dscl  .   create  /Users/<name-user-account>  IsHidden  0

The last character on the line is a zero.

Edit: Or this may be related to a macOS bug I've encountered on some of our organization's Macs. The last created user account "disappears" and cannot be accessed. I've never had the time to delve further into it once I discovered creating another user account brings back the ability to access the "missing" user account. It just moves the problem to the new user account.

Again, this is yet another example why backups are so important since sometimes it is easier or better to restore from a backup than to try to understand or fix the problem in other ways.

Interesting, just tried it here, no new user showed up, cannot reboot right now to see if that helps.

If you have a good current Backup might see if this works...

See if you can create a new administrator account by restarting the Setup Assistant:

1. Boot into Single User Mode: Start/restart your Mac. As soon as you hear the startup tone, press and hold ⌘ + S until you see a black screen with white lettering. (If you end up back on the login screen after a flash of the black screen with white lettering, enter your password and it will return to the black screen.)
2. Check and repair the drive by typing /sbin/fsck -fy then ↩ enter - as directed by the on-screen text.
3. Mount the drive as read-write by typing /sbin/mount -uw / then ↩ enter.
4. Remove the Apple Setup Done file by typing rm /var/db/.AppleSetupDone then ↩ enter.
5. Reboot by typing reboot then ↩ enter.
6. Complete the setup process, creating a new admin account.

Be very careful to notice the spaces in those Terminal Commands.

Once you've done that the computer reboots and it's like the first time you used the machine, except all your data will stile there. Your old accounts are all safe. From there you just change all other account passwords in the account preferences!!

Interesting. I ran the Mojave updates at the same time (security & safari) the other day and didn't think anything of it. Then I ran an update to Catalina today (unrelated, it was time for me to do it). After that I tried to create a new user and ran into this problem. So the issue could START with the Mojave security/safari installers but updating to Catalina does not fix them. Thought it was just a glitch until I was helping a user completely erase & reinstall Mojave on his machine and we ran into the same issue. But, again, he ran the security update too. We're having him erase and reinstall Mojave again but this time skip the security update. If that works I'll reply back again tomorrow & report my findings to Apple.

That was my suggestion early on, it does not appear to workin this situation, a reinstall of te OS, hopefully n Safe Mode is the Cure.

That’s the same reason I wanted to stay on Mojave - audio production. If I upgrade to Catalina I will need to spend another $200 to upgrade to a newer version of Digital Performer. I’ve been tempted to switch to LPX (free upgrades) but that will still cost me $200 to start plus all the time it takes to relearn something. Bummer.

https://mrmacintosh.com/mojave-2020-005-security-update-causing-major-problems-updated/

This article says that if you instal Safari 14 and then the security update you have these problems, but not if you install the Security update first.

After reinstalling my OS from Recovery Mode (Command R) the problem was fixed and I installed the Security Update and things seem to be fine. I'm in no hurry to update Safari though.

I was wrong, Catalina does fix the issue. I thought for sure I was still unable to create users but after another restart it seems to be allowing this again. admiral_koa is correct, the MrMacitosh article is very helpful.

OK, I went for it and updated Safari and all is fine, so it is the sequence of the upgrades. Security first, then Safari.

MrMacitosh is very helpful

👍

Any strange chrs in the name?

Safe Boot, (holding Shift key down at startup), does the problem occur in Safe Mode?

Safe mode attempts to repair Disks & clears lots of caches & loads safe Drivers, & prevents loading of 3rd party extensions, so if Safe Mode works try again in regular boot.

I couldn't find any info on this, so I started a thread about the Zoom not working. Then I found this thread. It's clearly a bug, but not one that seems to be well known yet.

It went away when I upgraded to Catalina.