How to Revert Mac Update

You can revert your Mac system update to the previous version using Time Machine.

Time Machine is available in the SMB server.

Make sure that your Mac system is running on macOS Sierra or later.

If not, you can’t use the Time Server.

Before reverting, take a backup of all the important data stored on your macOS.

Now, click the Apple icon and select the Restart option.

Wait for your Mac device to restart.

Once it is done, locate and hold down the Command and R buttons on your Mac system keyboard.
Hold down both the buttons until the Apple logo appears on your Mac system.
After that, release the Command & R buttons.
Choose the Restore option.
Click the Continue button.
Now, a list of available disks appears on the screen. Select the Time Machine backup you wish to restore and perform the on-screen instructions.
Once the reverting is done successfully, your Mac device starts up automatically.