Look for your startup disk in the left panel under Internal.
How to wipe Mac (format Macintosh HD) in Disk Utility:
Select the target Bluetooth device from the list.Please connect a USB keyboard and mouse in advance before following steps if you’re using a desktop Mac: iMac, Mac mini, or Mac Pro. Type sudo shutdown -r now and press Enter.
The NVRAM, formerly known as PRAM, refers to a small amount of special memory on Mac. If you're using macOS Mojave or earlier, please go to the Apple logo menu -> System Preferences -> iCloud -> Sign Out. Sign out of iCloud (macOS Catalina or later):
Wipe USB Drives: Erase Your Data Completely & Securely! What to Do Before You Sell, Give away, or Trade in a MacBookīefore talking about how to wipe MacBook (how to wipe a MacBook Pro to sell), I’d like to show users what they should do before erasing the Macintosh HD. What should you do? Do you need to take out the disk drive and ruin it? How to wipe a MacBook completely? All of these questions will be answered later. However, you need to remove the data completely when you plan to change a hard drive, sell/trade in the old Mac, or give away your MacBook to others. In general, you need to protect hard drive data well to prevent personal data loss/leakage.
Format: APFS or Mac OS Extended (Journaled), as recommended by Disk Utility.Click the Erase button in the toolbar, then enter the requested details:.Select Macintosh HD in the sidebar of Disk Utility.From the utilities window, select Disk Utility and click Continue.If asked, select a user you know the password for, then enter their administrator password.Start up from macOS Recovery: Turn on your Mac, then immediately press and hold these two keys until you see an Apple logo or other image: Command (⌘) and R.