If your Mac desktop looks different
If your desktop looks different from the last time you used your Mac, and the Mac has multiple users, another user may be currently logged in, and you may be using that person’s account.
Do any of the following:
Look in the menu bar in the upper-right corner of the screen. If fast user switching is turned on, the name of the current user or a generic icon is displayed there. You can turn on fast user switching in Control Center settings.
Click the fast user switching menu. The current user is identified by a checkmark in the menu. If you’re not the current user, you can use the fast user switching menu to log in. Choose your name, then log in.
In the Finder , choose Go > Home to go to the home folder.
If the home folder isn’t yours, choose Apple menu > Log Out, then log in as the correct user.
If you’re logged in as the correct user but the desktop looks different and other users have access to your Mac, it’s possible that another user changed your settings. To protect your Mac from being modified by others, see Set up your Mac to be secure.
It’s also possible that an administrator may be controlling how the desktop, windows, or Dock look and behave. If you have more questions, talk to the person who administers the Mac you’re using.
Your desktop may also look different if you turned on iCloud Desktop and Documents on this Mac, and then changed the desktop items on iCloud.com or another Mac, or on an iPhone or iPad where iCloud Drive is turned on. See Store files in iCloud Drive on Mac.