Hello @Ramya M​  Please follow the article below.

https://apeople.automationanywhere.com/s/article/Commands-like-Object-Cloning-Image-Recognition-Keystrokes-Etc-Do-Not-Work-In-Unattended-Mode-When-Autologin-Is-Enabled-And-Error-Out-With-Black-Screenshot-On-Failure/p>

What action can be performed to get out of lock screen before taking screenshot?

@RamyaM 

I assume you  have this issue during unattended mode of running.

Please make sure while disconnecting VM manually by Rt. click windows button and signout rather than disconnect. 

Also try below 

Step 1 : Have to use Regular deployment setting rather than RDP deployment

Step 2:  Please run below script whenever you are login into bot runner vdi (no need to sign out, disconnect just execute below script)

              --- Save file As DisconnectRDP_Lock.bat-------

for /f "skip=1 tokens=3" %%s in ('query user %USERNAME%') do (

  %windir%\System32\tscon.exe %%s /dest:console

)

rem Rundll32.exe user32.dll, LockWorkStation