• A 'Control Room' window will appear.

• The user will select ‘Search in all’.

• A 'Controls' window will appear in which the user will Search 'Screen Saver'.

• Now click on ‘Accept’.

• A 'Screen Saver' window will appear.
• In 'Screen Saver if computer is not in use' option, the user will select 'N' if the option not required.
• If the option is required to the user: 

1) The user will increase the 'Screen saver activate in Minutes' 

2) The user will increase the 'Screen saver password required after minutes'

• The user will now press 'ESC' key twice.

• Now click on ‘Yes’ to save the changes.

After following the above steps, the user will be able to disable Change user window.

Alternative Solution:-

Press 'Ctrl+U' key > User change window will be appear > Feed user id and password > Then press enter key > There is a option shown of Screen saver Default/Yes/No---"Default" > Then press enter.