An on-prem AD user has logon name user1@contoso.com and pre-Windows 2000 name CONTOSO\User1. For per-user FSLogix profile configuration on a domain-joined session host, how should you reference this user in the FSLogix registry settings?

FSLogix profile configuration, especially for per-user settings on domain-joined session hosts, typically uses the sAMAccountName (pre-Windows 2000 logon name) format. Therefore, CONTOSO\User1 is the correct way to reference the user in FSLogix registry settings. While user1@contoso.com is the UPN (User Principal Name), FSLogix often relies on the NetBIOS domain name and sAMAccountName for local domain-joined contexts. User1 is incomplete as it lacks the domain context. The SID (Security Identifier) S-1-5-21-4534338-1127018997-2609994386-5108 is a unique identifier but is not the standard or recommended format for direct user referencing in FSLogix registry configurations.