How to Migrate Your Mac's OS and Your Data to a New Drive

Choose the correct drive to install in your computer

Nothing will put the brakes on an installation like trying to install the wrong drive. Please double-check your Mac's model ID before proceeding (press the Option key then choose Apple Menu > System Information). Once you know the model ID, use the My Upgrades feature to find the right drive. If you're still not 100% sure, our sales representatives are happy to help.

Make sure you have a way to transfer your data

To transfer your data, you'll need both your original drive and your new drive, connected at the same time. For single-drive computers, you'll need a device to connect the old drive to your computer after your new drive is installed.

If you plan to use your old drive for external storage when the migration process is complete, you can install that drive into an enclosure. We offer many DIY kits with the external enclosure included. Depending on the drive’s capacity and connector type, you can use one of the following solutions to connect it an External Enclosure, the OWC Drive Dock, or the NewerTech Universal Drive Adapter. In some cases, you'll need a special enclosure for Apple's SSD.

If the Mac can hold both the new drive and the original drive (for example, a 2006-2012 Mac Pro, or a laptop or Mac mini with a Data Doubler) no enclosure should be necessary. Please contact our customer service team if you are still unsure of which solution is best.

Make sure you have a current backup

Make sure you have a current backup of your data on a separate drive before you continue. If you have a Time Machine backup already, you should be OK. If you don't use Time Machine, you can make a complete copy of your drive by cloning your data to a new hard drive in macOS. This will ensure you have a copy of your data on a separate physical device, in the unlikely event of accidental data loss during the upgrade.

Make sure you have means of installing your chosen OS

For Mac OS X 10.6 and earlier, you will need the OEM installer disc.

For Mac OS X 10.7 and later, you can use the recovery partition on the original drive. To make sure you have a functional recovery partition, restart your computer and immediately hold down the Command + R keys until the Apple logo appears. If your computer boots into a four-option menu then you have a functional recovery partition that can install the OS. If your computer boots normally to your desktop then you do not have a recovery partition.

If you’re using Mac OS X 10.7 and later and do not have a functional recovery partition, and your computer is found on this list (or is newer than what’s in the list), you can use the Internet Recovery feature built into your Mac. To make sure you have access to Internet Recovery, restart your computer and immediately hold down the Command + Option + R keys until you see a spinning globe logo. If your computer does not have an internet connection it will prompt you to connect to a wireless network. If your computer boots into a four-option menu then you have the ability to use Internet Recovery.

If you are unable to use Internet Recovery you can create a USB installer using DiskMaker X, in order to install a clean OS.

Install your new drive

If you need help installing your drive, OWC has an extensive library of instructional videos that walk you step-by-step through drive installation for most user-upgradable Mac models.

Connect your old drive externally

Note: This step is only for systems where the original drive has been removed. Systems that have both new and old drives inside the Mac can skip to Step 7.

Once you have installed the new drive into your Mac, connect the old drive to the external enclosure or adapter, as mentioned in Step 2, then connect the now-external drive to your Mac using the appropriate cable. Once this is done proceed to Step 7.

Boot to your installer

Boot into whichever installer method worked for you in Step 4.

Note: Aura Pro X2, Aura Pro X, and Aura N SSDs require the Command + Option + R or flash drive methods.

Format your new drive

The steps involved in formatting your new drive depend on which version of macOS you're using.

For macOS 10.12.6 and earlier:
Use Disk Utility to format the new drive. You can find Disk Utility in the Utilities menu at the top; in Mac OS X 10.7 and later, it's also in the main list at the center of the screen.

Once Disk Utility is open, select the newly installed disk from the list on the left. Once you have the disk selected, click on the 'Erase' tab on the right. Set the Volume Format to 'Mac OS Extended (Journaled)'; The name can be anything you want. Once those options are set, click the 'Erase…' button.

For macOS 10.13 and later:
Use Disk Utility to format the new drive. This will be Option 4 in the menu option that is presented when you boot up into recovery.

Once Disk Utility is open, select the View button on the upper left of the window and select Show all Devices. If your drive does not show in the sidebar, quit Disk Utility and then reselect it from the menu. Once you have the disk selected, click on the 'Erase' tab on the right.

Set the Volume Format to 'Mac OS Extended (Journaled)'; for SSDs being installed as internal boot drives, select 'APFS' (Apple File System).

Note: Rotational drives and Fusion drives can only be formatted as Mac OS Extended (Journaled). The name can be anything you want but should be a different name from the startup drive being replaced. Once those options are set, click the 'Erase…' button.

Fresh OS X / macOS Install or Restore from Time Machine?

At this point, you need to decide whether you're going to perform a fresh OS install or restore your data from Time Machine. We highly recommend you perform a fresh install of macOS, and then use Apple's Migration Assistant to migrate the data to the new drive. This should provide a better starting point and will ensure your new drive is set up with an Apple recovery partition.

Installing a clean copy of OS X / macOS on your new drive
Once you've formatted the drive, you can close Disk Utility. If you're in Mac OS X 10.7 and later, you'll need to select the 'Reinstall Mac OS X' option from the Utilities screen. In earlier OS versions, quitting Disk Utility will take you back to the installer.

Follow the steps as they are presented, making sure to select the new drive (the one you just formatted in the previous step) as the install location. The OS installers are simple to use; just follow the on-screen prompts. Once you have filled in the required information, the installation will begin. This can take a while, depending on your internet connection speed. Fortunately, the process from this point is automated, so you can do something else while waiting for the install to complete.

Once this step is complete, proceed to Step 10.

Restoring the OS and user data from Time Machine
Note: This step is for those using Mac OS X 10.7 and later.

Once the drive is formatted you can opt to select Restore from Time Machine. This method allows you to restore the OS and your user information back to the drive.

Once this step is complete, skip to Step 11.

Use Migration Assistant to transfer data to the newly installed OS on your drive

Once the OS has been installed, your computer will restart to the new drive and walk you through the final setup steps. Continue through the on-screen prompts until you’re asked if you'd like to import user data from another system. This part of the setup process uses Apple's built-in Migration Assistant utility. If for some reason you skip the initial setup, you can find Migration Assistant by navigating to Applications > Utilities. The Migration Assistant will scan for available drives, showing you a list. Select your drive once it appears, then click 'Continue'.

The next screen will list the data types you can transfer. Select any user accounts you want to install on your new drive, as well as any applications and network settings. You can either select them all, or you can select/deselect items individually by expanding the folders via the disclosure triangles. There is an option for 'Files and Folders' which you will likely want to copy over as well, since some applications install some settings in non-standard places.

Once you have selected the items you want to copy to the new system drive, click the 'Transfer' button. Depending on how much data is being is being copied, this may take a while. After Migration Assistant finishes you can continue the rest of the process. Once the setup is complete your computer will bring you to the login screen or your desktop.

Use Migration Assistant to transfer data to the newly installed OS on your drive

Note: Only perform this step if you installed a clean copy of OS X / macOS on your new drive in Step 9. Otherwise, proceed to Step 11.

In most cases, there will be updates immediately available for the OS X or macOS version you just installed. Once the initial setup is finished, follow the normal process for updating, based on your OS version (some versions require you to open the App Store application, others can be updated by choosing Apple > Software Update….) Restart if necessary and repeat the process until there are no additional updates to install.

Repair disk permissions

Note: If you are using macOS 10.12 and later skip to Step 13.

For Mac OS X 10.6-10.11: Use Disk Utility (Applications > Utilities > Disk Utility) to repair permissions on your new drive. Select the new OS X volume in the list on the left, then click on the 'First Aid' tab, then click on 'Repair Disk Permissions'.

Double-check your files

Run all your apps and go through your files to make sure everything is working, and nothing is missing. You may have to re-authorize some applications or, in very rare cases, reinstall the application. Make sure everything is as you want it before continuing.

You're Done!

Once you've checked to make sure your data came through correctly, you're ready to go. Now you can either erase your old drive in the external enclosure and use it for other purposes or save it for posterity.