After user session Launched, the "current username" in Citrix Studio shows "-".
Solution 2: "cmstart.exe" is missing in the registry key
"cmstart.exe" should be in the registry key: HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\AppSetup. Please add "cmstart.exe" if the data does not exist.
The process "userinit.exe" does not start the process "cmstart.exe" successfully.
This kind of issue usually needs Process Monitor logs to check. In the Process Monitor log, filtering the process "userinit.exe" to check if "cmstart.exe" is created by "userinit.exe" or not.
"userinit.exe" will not create "cmstart.exe" if the related registry key or process path is missing, which will cause the username cannot be send back to DDC.