To secure erase an SSD (Ensure its contents cannot be recovered)
The usual secure erase isn't available in Disk Utility. The old technique is not recommended for SSDs. Alternative is to decrypt, then re-encrypt the whole drive.
Go to Settings > Security and Privacy > Turn off Filevault Wait for a long time while the drive is decrypted Re-enable Filevault and set a new key Wait for along time again while the drive re-encrypts
A Better Way?
Boot from recovery mode, internet, or external disk Erase the disk as encrypted HFS or APFS Supply a complex key Fill the disk with zeros, using mkfile Terminal command is mkfile SIZE FILENAME For example: mkfile 100G File100G Erase the disk again, without encryption
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