Why does Migration Assistant get stuck on "Preparing"?
Short answer: Migration Assistant's "Preparing" phase is when it indexes the source Mac — scanning every file and calculating how long the transfer will take. It gets stuck when the connection between the two Macs is unstable or blocked: the macOS Firewall is rejecting the migration port, both machines are on different Wi-Fi channels, a USB-C cable that does not support full data transfer speeds is being used, or iCloud sync is still modifying files on the source Mac faster than Migration Assistant can count them. Addressing these four issues resolves the hang in most cases.
How to fix Migration Assistant stuck on "Preparing"
Step 1: Disable macOS Firewall on both Macs
The macOS Firewall (System Settings → Network → Firewall) can block the Bonjour service and the migration protocol port that Migration Assistant uses to communicate between the two machines. Even with Firewall set to "Block all incoming connections" on just one machine, the handshake fails and the Preparing stage never completes. Turn off the Firewall on both Macs before starting Migration Assistant, then re-enable it after the transfer is done. This single change fixes the "Preparing" hang in roughly half of the cases we encounter.
Step 2: Switch to a USB-C or Thunderbolt cable connection
Wi-Fi migration requires both Macs to be on the same network band — both on 5 GHz, or both on 2.4 GHz. If one is automatically assigned to 2.4 GHz (common on crowded apartment-building Wi-Fi networks in India) and the other is on 5 GHz, the two Macs are technically on different channels even though they appear connected. Migration Assistant interprets this as an unreliable link and keeps the "Preparing" progress bar frozen. The reliable fix is a direct cable connection: USB-C to USB-C or Thunderbolt 4 cable between the two machines. In the Migration Assistant screen, choose "From Mac" and connect via cable. Cable transfers are 5–10× faster than Wi-Fi for typical 200–500 GB migrations and sidestep all the Wi-Fi band issues entirely.
Step 3: Pause iCloud Drive sync on the source Mac
Migration Assistant builds a file count and size estimate during "Preparing." If iCloud Drive (System Settings → Apple ID → iCloud → iCloud Drive) is actively syncing on the source Mac — downloading or uploading files — the file list keeps changing as Migration Assistant tries to count it. The preparation phase cannot complete a consistent snapshot, so it keeps restarting the count. Pause iCloud sync: open System Settings → Apple ID → iCloud, toggle off iCloud Drive temporarily. Also quit any active backup applications (Time Machine, Carbon Copy Cloner, Backblaze) that are writing to the source drive during migration. After Migration Assistant completes, turn iCloud Drive back on.
Step 4: The India angle — slow broadband impacting iCloud file availability
A factor unique to India is that many MacBook users have a large proportion of their files stored as iCloud-only (not downloaded locally), especially after upgrading to a new Mac and relying heavily on iCloud Storage. Migration Assistant can only transfer files that are physically present on the source Mac's drive. Files that exist only in iCloud are not transferred. Our guide on fixing iCloud Drive sync issues covers how to force-download all your iCloud files before starting a migration. With typical Indian broadband speeds of 50–100 Mbps, downloading 200–300 GB from iCloud before migration can take 5–8 hours — plan accordingly. Doing this step ahead of the migration prevents the "Preparing" hang caused by iCloud contention.
When to call a laptop repair service
When DIY ends
Contact a specialist if: the cable connection shows "connected" but no devices appear in Migration Assistant on the destination Mac (may indicate a USB-C port issue on one of the machines); if the source Mac's drive has file system errors that cause Migration Assistant to freeze during cataloguing; or if you need to migrate from an Intel MacBook to an M-series MacBook and want to ensure Rosetta 2 compatibility for all Intel apps is handled correctly.
Typical cost in India
Data migration between Macs at a service centre: ₹800–₹1,500. If the source Mac has a failing drive that needs data recovery before migration: ₹1,500–₹5,000. USB-C port repair on the source or destination Mac if the port is damaged: ₹2,500–₹6,000.
A note from the LRW Engineer Team
Migration Assistant is almost always fixable at the software or connection level — we rarely see a case where it cannot be made to work with the right cable and the right settings. The most common mistake is attempting a large migration over a congested apartment Wi-Fi network while iCloud is actively syncing in the background. For a clean migration, use a cable, turn off iCloud sync, turn off Firewall, and let it run overnight. The transfer itself — once past the "Preparing" phase — is reliable and rarely needs intervention.