Mac Migration Pitfalls Guide: Real Experience from Migrating Two Machines

How do you get all the content from your old Mac transferred to a new machine in one go? Can you just use Migration Assistant right after unboxing? I've been through the migration process with two different machines and ran into the same issues both times. Here's my guide to elegant migration, hoping it can help you out.

I recently wrestled with two computers and discovered some problems during the new Mac migration process. Since both machines had the same issues, this isn't just a coincidence—it might be a small system bug.

Hardware Setup

Here are the two machines I purchased (proof this isn't clickbait) - both are 14-inch MacBook Pros but with different configurations: first was 10-core, second was 14-core.

Apple's official order records showing the different status of two 14-inch MacBook Pros

Refund details page for the first machine

The second 14-inch MacBook Pro successfully delivered

I returned the first one because of a power module issue - the MagSafe 3 port kept flickering when plugged in. I tried a bunch of online tutorials but nothing worked, so I contacted Apple support for a return. This was probably just an isolated case - my previous M3 had been running fine for two years without any issues.

Following the principle of avoiding first batch units, I got the 14-core model for the second purchase, and upgraded the power from 70W to 90W.

What You Need to Watch Out For During Migration

1. Tool Preparation

First, if your old machine has a lot of data (mine was 440GB out of 500GB, which was another reason for upgrading), try to get a USB-C cable with connectors on both ends. Apple recommends Thunderbolt 5 for faster migration, but it's too expensive, so I just used what I had on hand. Don't worry if you don't have one though - a friend successfully migrated using WiFi/Ethernet.

2. New Mac Setup Steps

Step 1: Boot into the system first Boot your new Mac into the system - you can skip logging in and skip any optional setup steps. Once you're in, update the system first.

Step 2: System update Settings → General → Software Update. This is a necessary step - the first Mac prompted me to update the system during migration, while the second one seemed to already have the latest system and didn't prompt.

Step 3: Erase all content and reset the machine Settings → General → Erase All Content and Settings. This step mainly resets the new Mac to prepare for migration.

Step 4: Reactivate After erasing and restarting, you'll need to connect to the internet for activation. After activation, it will restart again and enter the system. Now switch to working on the old Mac.

3. Old Mac Setup Steps

Step 1: System update Same as the new Mac above. If you already have the latest system, just restart once.

Step 2: Connect the cable Connect the prepared cable to the new Mac. The old Mac might show a new device connection prompt - just accept it.

Step 3: Open Migration Assistant Open Migration Assistant and select "To another Mac".

Migration Assistant application icon in macOS

4. Continue with New Mac

Now you can continue following the new Mac's setup guide until the Migration Assistant interface appears. Select "From a Mac, Time Machine backup, or startup disk".

At this point, it will ask you to confirm some settings, then click continue on the old Mac. If you're using a USB-C connection, make sure it shows "Point-to-Point" as in the image below. Also make sure that for the duration of migration (about 10 minutes or so), the new Mac's screen stays bright and active.

Select "From a Mac, Time Machine backup, or startup disk" on the new machine

Actual migration progress interface showing "Point-to-Point" connection and transfer speed

Real scenario of two MacBook Pros connected via cable for data migration

The Problem Both Machines Encountered

Key Issue: Screen Sleep Causes Migration Failure

When I used Migration Assistant right after booting the new Mac (also using cable connection), the new Mac's screen would dim after just a few minutes during migration. I had to keep moving the mouse to keep it bright. If I didn't keep it bright and let it completely sleep, I'd find that the migration on the old Mac would stop after a few minutes, with no more progress bar or data increases. Clicking on the new Mac would show the progress bar still wasn't moving, and I'd have to cancel and force reset (the first time it migrated 800,000+ files and then showed migration problems...).

Solution: So please make sure the new Mac stays bright during migration. From what I've seen, keeping it bright prevents migration failures.

Handling App Issues After Migration

If some software shows "damaged and can't be opened. You should move it to Trash" errors after migration, you can try the following:

Method 1: Enable Any Source

1️⃣ Open Launchpad, select Terminal, and enter:

sudo spctl --master-disable

Then press Enter, continue to enter your password (password input is invisible), then press Enter.

Next, open System Preferences, select Security & Privacy, select General, and you can see Anywhere is now selected.

Method 2: Remove App Quarantine Attributes

2️⃣ In Terminal, paste and copy this command (note there's a space at the end):

sudo xattr -r -d com.apple.quarantine 

Don't press Enter yet! Don't press Enter yet! Don't press Enter yet! Don't press Enter yet!

Then open "Finder" and go to the "Applications" directory, find the software icon, and drag the icon to the Terminal window you just had. You'll get a combination like this (as shown in the image):

sudo xattr -r -d com.apple.quarantine /Applications/WebStrom.app

Return to the Terminal window, press Enter, enter your system password and press Enter.

Practical Tips Summary

Based on my two migration experiences, here are the most important points:

Keys to Success:

• Update both new and old Mac systems first
• Reset the new Mac first before migration
• Keep the new Mac screen bright during migration
• Use USB-C cable connection, confirm it shows "Point-to-Point"
• Be patient - my 440GB data took about 3-4 hours

Easy Pitfalls:

• Starting migration right after unboxing without updating the system
• Letting the new Mac screen sleep during migration
• Being impatient and canceling to restart

Data Volume Reference: My data was 440GB out of 500GB, including lots of development environments, applications, and personal files. If your data volume is similar, allow half a day to be safe.

Want to check your Mac compatibility? Use our compatibility checker to verify your system capabilities.

References

Some content from:

• https://support.apple.com/zh-cn/102613
• https://zhuanlan.zhihu.com/p/135948430