Mac

Migration Assistant stuck when transferring to a new Mac

Migration Assistant transfers can stall due to a slow or interrupted network connection, a very large amount of data, or a conflict with security software running during the transfer.

Difficulty
Moderate
Time
1–6 hours
DIY cost
$0
Pro cost
$100–$200

Symptoms

  • Progress bar stays at the same point for a long time
  • Estimated time remaining keeps increasing instead of decreasing
  • Transfer is happening over Wi-Fi rather than a direct cable connection
  • One or both Macs show as still 'connected' but with no visible progress

Likely causes

  • CommonA slow or unstable Wi-Fi connection during a wireless transferWireless transfers are far more prone to stalling than a direct cable connection.
  • CommonAn extremely large amount of data (many hundreds of gigabytes) simply taking a long timeSome stages can look stalled while actually processing efficiently in the background.
  • PossibleThird-party security software interfering with the transfer processSome antivirus or firewall tools can disrupt Migration Assistant's network communication.
  • PossibleOne of the Macs going to sleep during the transferThis can interrupt or slow the process significantly.
  • PossibleA corrupted file or backup causing the transfer to hang on a specific itemThis is less common but can cause a true, indefinite stall.

What to do

  1. If transferring over Wi-Fi, switch to a direct cable connection (Thunderbolt or USB-C to USB-C) if both Macs support it, which is dramatically faster and more reliable.
  2. Make sure both Macs are plugged into power and set to never sleep during the transfer (System Settings > Lock Screen / Battery).
  3. Temporarily disable third-party security or firewall software on both Macs during the transfer.
  4. Give it more time if you're transferring a very large amount of data, since multi-hundred-gigabyte transfers can take many hours.
  5. If it's been stalled at the exact same point with no progress for over an hour with no data movement indicators, consider canceling and restarting the transfer.
  6. Restart both Macs before trying again if you do need to cancel and retry.
  7. Consider transferring from a Time Machine backup instead of directly Mac-to-Mac if direct transfer keeps failing.
  8. As a fallback, manually copy your most important files via an external drive if Migration Assistant continues to fail.

Tools and parts

  • Thunderbolt or USB-C cable (for direct transfer)

When to call a pro

If transfers consistently fail even with a direct cable connection and security software disabled, an Apple-authorized shop can help complete the migration or transfer files manually.

Safety

Generally low risk

Generally low risk for a careful person. Stop if anything looks different from what this guide describes.

Related guides

Operator provides AI-generated troubleshooting information. It can be wrong. For safety-critical, electrical, gas, structural, medical, automotive safety, or other high-risk problems, consult a qualified professional.