Secure Erase Mac SSD

Follow these steps to securely erase your Mac SSD.

This procedure serves as a calming measure 💊 if you find it odd that your SSD can be securely erased in just seconds 😉

TL;DR:

1. Encrypt and Erase: Use Disk Utility to erase the SSD with APFS (Encrypted) format.
2. Overwrite with Random Data: Run a script in Terminal to fill the SSD with random data until full.
3. Erase Again: Use Disk Utility to erase the SSD again, 🚮 discarding the encryption key ✅ .

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Full Procedure

1. Boot into Recovery Mode

• Restart your Mac and hold down Command (⌘) + R until you see the Apple logo or spinning globe.

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2. Use Disk Utility to Erase the Disk

1. Select Disk Utility from the macOS Utilities window.
2. Choose Macintosh HD → Erase.
3. Select APFS (Encrypted), set a secure password, and confirm the erasure.

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3. Prepare for Secure Overwriting

1. Close Disk Utility.

2. Open Safari from the macOS Utilities window.

3. Navigate to the URL: https://github.com/tbsbdr/Secure-erase-Mac-SSD/.

4. Copy the following script:

   #!/bin/bash
   
   # Define the mount point for the target disk
   MOUNT_POINT="/Volumes/Macintosh HD"
   
   # Check if the mount point exists
   if [ ! -d "$MOUNT_POINT" ]; then
       echo "Error: Mount point $MOUNT_POINT does not exist. Ensure /dev/disk3s1 is mounted."
       exit 1
   fi
   
   # Change directory to the mount point
   cd "$MOUNT_POINT" || exit
   
   # Set file index for naming
   file_index=1
   
   # Loop to write 1GB files until the storage is full
   while :; do
       file_name="random_data_$file_index.bin"
   
       # Use 'dd' to generate random data and write it to a file
       echo "Creating $file_name..."
       dd if=/dev/urandom of="$file_name" bs=1M count=1024 status=progress
   
       # Check if the write was successful
       if [ $? -ne 0 ]; then
           echo "Error writing file. Likely the storage is full."
           break
       fi
   
       ((file_index++))
   done
   
   echo "Storage is full or an error occurred. Written $((file_index-1)) files."
   exit 0

5. Close Safari.

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4. Execute the Script

1. Open Utilities → Terminal.
2. Create the script file using vi:

   vi erase.sh

3. Enter the script into vi:

• Press i to enter Insert Mode.
• Paste the copied script (Command + V).
• Save the file:
  • Press ESC.
  • Type :wq, then press Enter.

4. Make the script executable:

   chmod +x erase.sh

5. Run the script:

   ./erase.sh

6. Wait for approximately 5 minutes (or longer, depending on SSD size) for the script to complete.

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5. Finalize the Erasure

1. Open Disk Utility again.
2. Select Macintosh HD → Erase.
3. Choose APFS (Encrypted) or any format of your choice.
   • This step discards the encryption key set earlier, effectively scrambling the SSD data.

Done! ✅

Your SSD is securely erased, and all data traces have been removed.