To allow the FDE login screen to remember the last logged in username, you will have to configure the Full Disk Encryption Workstation policy:

Note: Username caching is only available for UEFI workstations.

Configure the Allow FDE Username Caching policy to Yes by following the article below:

KB229 - How do I modify workstation policy? 

Once the setting has been configured, after the first user has logged in, the username will be cached and displayed at the next reboot as shown below:

If you want to check that the policy has been applied, open the Windows Registry and check that the ‘FDEStickyUsername’ policy value is set to (1) in the pathway as shown below.

[HKEY_LOCAL_MACHINE\SOFTWARE\DESlock\Client\Policy]

FDEStickyUsername = 1 

Keywords: cached credentials remember fde login