Using iCloud means you do not need an external drive. You can also use iCloud to backup your files. Click on Erase to allow Time Machine to erase all the information that is already on the backup drive. If the disk is not formatted according to Time Machine’s standards, you will be asked to erase it first. Select your external drive from the list provided.Click on Preferences > Select Backup Disk.Select the Time Machine menu in the menu bar.If Time Machine does not prompt you about using your drive for backups then you can add it manually. To start a manual backup, select the menu bar in Time Machine and click on Back Up Now.If this is your first time using Time Machine, you will be asked if you want to use the drive for the backup.Connect the external storage device to your Mac.You can backup files using Time Machine with an external hard drive or large thumb drive.

This saves your files for whatever device will be replacing your Mac. Create a Backupįirst and foremost, create a backup of your files. This is not because erasing the hard drive takes a long time, but because there are things you must make sure are deleted and disconnected. Several things need to be done to thoroughly wipe your Mac computer. This is for the sake of your security and privacy - and common courtesy to the new owner. Getting ready to sell your Mac computer and upgrade to a new machine? Before letting it go into someone else’s hands, you need to make sure all your data is wiped.

How to erase imac hard drive