How do I resolve duplicate user icons on Mac Lock Screen?

Fix Duplicate User Icons on Your Mac Lock Screen

Device: MacBook Air 15-inch | macOS: 26.6

If two user accounts have different names but display the same picture, follow these steps in order.

1. Check the account

Open Apple menu  >> System Settings >> Users & Groups. Select the account whose picture you want to change and confirm you’ve chosen the correct user.

Apple guide: Change Users & Groups settings

2. Change the picture

Click the current picture, choose a different avatar or custom image, adjust it if needed, and click Save.

Apple guide: Change your login picture

3. Check the login status

If the picture won’t change, check whether the target user is logged in.

You can’t change another user’s login picture while that user is logged in. Ask them to log out or change their own picture.

4. Restart your Mac

If the picture changes in System Settings but not on the Lock Screen, restart your Mac and check both icons again.

5. Diagnose or contact Apple Support

• Picture won’t change: Recheck the selected account and login status.

• Different pictures in System Settings, but identical icons on the Lock Screen: Restart and check again.

• Icons become identical again after restarting: If the problem persists, contact Apple Support.

Visit Apple Support for Mac and explain what you tried and whether the pictures differ in System Settings.

Important: Don’t delete accounts, rename home folders, or use Terminal commands as an initial fix.

Re: "Mac lock screen problem :There are two users with different names on Mac lock screen. But the icons are the same. I can't just change one icon. Please help!"

Seems, if logged in, each user may need to change their own icon:

Apple support provides an article (link below) that may help with that:

See how you can: Change your login picture on Mac