Guest user Login

Hi mallikarjun80, thanks for posting here in Apple Support Communities. We understand that you're seeing a Guest user login on your Mac, which you've never created. By any chance, do you allow others to use your Mac computer? If not, would you be okay with performing the following steps? These same steps can be found here: Set up users, guests, and groups on Mac - Apple Support

1. Login as an admin user.
2. Go into System Preferences > Users & Groups.
3. Click on the lock icon and enter the current user's password to open the lock.
4. Select Guest User.
5. Click once on the checkbox next to "Allow guests to log in to this computer", to toggle this setting opposite of how you want it to be configured:

• If there was already a checkmark in this box: remove the checkmark.
• If there was not a checkmark in this box: put a checkmark in the box.

Once those steps are done:

1. Quit System Preferences.
2. Go back into System Preferences > Users & Groups.
3. Click on the lock icon and enter the current user's password to open the lock.
4. Select Guest User.
5. Configure the checkbox next to "Allow guests to log in to this computer" to your desired setting.
6. Verify that the correct status is now shown under "Guest User" (on the left side of the window): 

• When there is a checkmark shown next to "Allow guests to log in…", the status shown under Guest User should be "Login only" or "Login, Sharing" in macOS Catalina, or "Enabled, Managed", "Login only", or "Login, Sharing" in macOS Mojave or earlier.
• When there is a not checkmark shown next to "Allow guests to log in…", the status shown under Guest User should be "Off" or "Sharing only".

Next:

1. Select Apple menu > Log Out [user name] > Log Out. Is Guest User now shown on the login window?
2. Click the Restart button on the login window. Is Guest User shown on the login screen?

We look forward to hearing back from you with the results.

Cheers!