I have
EXACTLY THE SAME ISSUE now, symtoms are the same. Also newly created users don't show up in login screen. Luckily it is possible to sign in to all accounts, by using "Other User" method, like similarly schools or enterprises have this in their computers, which are in domain. (I think it is also possible with Remote Desktop, if hidden accounts are Administrators or Standard users in Remote Desktop Users group, you can set that up from your only accessable account too). It's a little uncomfortable, because every time you need to enter username too, but it works. Yeah, you can say that resseting Windows fixed you're problem, but it wasn't entirely 100% correct solution.
Enable "Other User" method using registry:
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System]
"dontdisplaylastusername"=dword:00000001
or to disable this and return to default way, just change 1 to 0 or delete this entry.
I'm also currently looking for the right solution, I dont wan't to reset Windows just for this issue, but so far I didn't find any solution. Maybe "dirty" upgrade to the same Windows version will do that fix, but I don't want to do that now, because in my opinion also this fix is not entirely correct solution.
I have Windows 11 and Users folder is located in drive D, in this way D:\Users, by using this tutorial:
Move Users Folder Location in Windows 10, and everything worked, no single one issue or programs trying to access %userprofile% in drive C. This is also supported by Microsoft:
Upgrade to Windows versions that is before Windows 10 is blocked if Users and ProgramData directories are changed. I really believe that this is not somehow connected in any way to this issue, because
your-evil-twin said that in his computer users folders were been in C:\Users folder:
Their profiles are still in C:/Users, yes.
In my case this problem happened after I tried to delete a partition by using Disk Managment, which was meant for temporary use, but for unknown reasons it didn't allow me to delete this partition (button greyed out), so instead I was using diskpart in command prompt. Now it started to clean this partition, but in the end it also failed, saying something about pagefile (later I looked up pagefile settings and pagefile was automatically regulated for all drives). And from this moment Windows Explorer restarted and didn't load back correctly, I couldn't browse my files nor even open Start menu. So I decided to reboot the computer and after that I find out that I'm unable to sign in to any account. Later I found out that Windows for unknown reasons randomly changed drive letters for all partitions except for Windows partition C: This is what caused to be unable to sign in to any accounts, because Windows couldn't find D:\Users folder anymore. After that I did
this - first answer by Jason Corchuelo, which allows me to open command promt from the login screen, then I opened Disk Managment and changed drive letters back as they must be (this can't be easily done from WinRE (Windows Recovery Enviorement), because changes made in Disk Managment from WinRE only affects WinRE not the actual Windows OS. (To do that in WinRE as well, I guess you would need to load registry hives and et cetera.) I rebooted computer again and I was able to sign in to my account again (which was the last one used before Windows Explorer crash), but every other accounts dissapeared from login screen.
I agree it's a long read, but I hope it will help for someone else who gets this trouble too.