How to Use Target Disk Mode and Share Mode on Mac Computers: A Complete Guide

What Target Disk Mode and Share Disk Mode Do

Target Disk Mode (Intel Macs) and Share Disk Mode (Apple Silicon Macs) let one Mac act as an external storage device. After the connection is established, the other Mac can open the drive directly in Finder and copy, repair, or back up its data.

These modes are useful for:

• Transferring large files between computers

• Migrating data from an old Mac to a new one

• Recovering files from a Mac that will not boot

• Repairing or formatting a drive using Disk Utility

• Running maintenance operations such as First Aid

Both methods rely on a direct cable connection and bypass Wi-Fi entirely for faster and more stable performance.

What You Need Before You Start

Before starting, review the hardware and software requirements to avoid connection issues.

Hardware Requirements

You will need:

• Two Mac computers

• A compatible cable between them

Cable Requirements

Cable compatibility is critical:

• If either Mac runs macOS Big Sur (11) or later, you must use a Thunderbolt cable.

• Older Intel models may support USB-C, USB, Thunderbolt, or FireWire depending on ports.

• All Apple Silicon models support USB-C and Thunderbolt.

Power and Stability

Keep both Macs connected to power or charged to ensure the connection is not interrupted during transfers.

Software Preparations

To avoid mounting issues:

• Temporarily disable FileVault on both Macs
  (System Settings → Privacy & Security → FileVault)

• Update macOS to the latest version

• Turn off VPN, firewalls, or antivirus tools if they interfere with detection or migration

How to Use Target Disk Mode on Intel Macs

The following steps apply to Intel-based Macs.

Step 1: Connect the Two Macs

Use the appropriate cable based on your models and operating system versions.

Step 2: Enter Target Disk Mode

You can enter Target Disk Mode in one of two ways:

If the Mac is off

• Hold the T key

• Press the power button

• Continue holding T until a Thunderbolt or FireWire icon appears

If the Mac is on

• Open Apple menu → System Settings → General → Startup Disk

• Select Restart in Target Disk Mode

Step 3: Access the Disk on the Other Mac

The target Mac’s internal drive appears in Finder as an external disk.
You can now drag files to or from it, use Disk Utility, or copy the entire drive.

Step 4: Exit Target Disk Mode Safely

• Eject the target disk in Finder

• Shut down the target Mac

• Disconnect the cable when the shutdown is complete

How to Use Share Disk Mode on Apple Silicon Macs

Apple Silicon Macs do not support classic Target Disk Mode. Instead, they use Share Disk Mode through macOS Recovery.

Step 1: Connect the Two Macs

Use a USB-C or Thunderbolt cable.

Step 2: Shut Down the Target Mac

Ensure the Mac you plan to access is fully powered off.

Step 3: Enter macOS Recovery

• Press and hold the power button

• Release when you see Loading Startup Options

Step 4: Continue to Recovery

• Select Options → Continue

• Enter your administrator password if prompted

Step 5: Start Share Disk

• In the macOS Utilities window, open the menu bar

• Select Utilities → Share Disk

Step 6: Choose a Disk or Volume

Select the internal disk or volume you want to access, then click Start Sharing.

Step 7: Access the Shared Disk

On the host Mac:

• Open Finder

• Select Network from the sidebar

• Double-click the shared Mac to connect as a guest or authenticated user

Step 8: Stop Sharing

When finished:

• Return to the Share Disk window

• Click Stop Sharing

• Shut down the target Mac if no further operations are needed

Advanced Uses You Should Know About

Target Disk Mode and Share Disk Mode can support more than basic file transfers.

Booting From Another Mac’s Drive

If both Macs are the same model and run the same macOS version, the host Mac can boot directly from the target Mac’s internal drive.

Steps:

1. Put the source Mac in Target Disk Mode

2. Start the other Mac while holding Option

3. Select the source drive to boot from

This method helps diagnose software issues or access macOS tools on a non-booting Mac.

Disk Utility Operations

When the target drive appears on the host Mac, you can:

• Format or erase the drive

• Create or remove partitions

• Run First Aid to repair common disk errors

• Prepare the drive for macOS installation

Important Warnings

• These modes cannot repair hardware problems.
  Signs of physical drive failure include:

  • Clicking or scraping noises

  • Extremely slow performance

  • Recurring read/write errors

• Accessing a failing drive in Target Disk Mode may worsen the damage.
  Stop immediately if such symptoms occur.

Troubleshooting When the Disk Doesn’t Show Up