not possible to login window

[vz]

Hello dear Community,

overnight the entire login screen disappeared two managed silicon Macs, MacOS 14.5.
The login screen only shows a guest account, which is not available either because the FileVault is actived.
I was able to access the hard drive using Target Mode and the data and user folders are still there. 

Has this ever happened to anyone? What could be the causes? 
I would be grateful for any tips.

[mschlosser]

I believe if accounts aren't listed at the FV decryption window, it means, that the accounts that are missing no longer have a secure token and thus lack volume ownership. Volume ownership is required on modern macOS for FV decryption. 

More info about volume ownership is at the following links.

If no known account still has a secure token, restoring from a backup is the most straightforward assuming one exists. Always best to ensure a known account to IT is a token holder, before a machine is issued. Also best to setup escrowing FV recovery codes in your MDM

https://support.apple.com/guide/deployment/use-secure-and-bootstrap-tokens-dep24dbdcf9e/web

https://derflounder.wordpress.com/2023/03/10/granting-volume-owner-status-on-apple-silicon-macs/

[vz · Accepted solution]

Found a solution with Jamf Support: pressing opt-cmd-return brings back the login mask.

Looks like a MacOS bug, but not a clue how to reduplicate it.