Setting up a new Mac: Migrate or clean install?

“If you’ve just bought a new Mac, and you’re upgrading from an older computer, you want all of your files and data to be accessible on the new machine,” Kirk McElhearn writes for Intego’s Mac Security Blog. “But when setting up a new Mac, should you migrate or do a clean installation?”

“When you buy a new Mac, it might be a good idea to do a clean installation; starting from scratch, with a brand-new operating system, and adding the files that you need manually,” McElhearn writes. “When you do a clean installation, you let OS X run its Setup Assistant and create a new, empty user account. During the process, you enter some information, such as your Apple ID, so your iCloud account is activated, but, for the most part, your Mac will be a tabula rasa.”

“If you go this route, you then need to manually copy files from your old Mac, or from a backup. This part of the process can be time-consuming, but it can allow you to sift through your files to find what you really need, and slim down your Mac,” McElhearn writes. “I did so this year, for the first time in many years, and many Macs, and was surprised to find how much I didn’t copy… While I don’t recommend doing a clean installation for each new Mac you get, or for each OS X update, it’s a good idea to do it every few years. Just make sure to keep a backup in case there are any files you need to find that you didn’t copy over the first time around.”

Much more in the full article – recommended – here.

MacDailyNews Take: We performed clean installations of our 11-inch MacBook Air units (256GB Flash Storage, so space is at a premium) back in March and we couldn’t be happier with these units. They are easily the best portable (and most portable) Macs we’ve ever used (specs below).

Specs for MacDailyNews’ 11-inch MacBook Air (Early 2014) units:
• 1.7GHz Dual-Core Intel Core i7, Turbo Boost up to 3.3GHz
• 256GB Flash Storage


  1. Clean install is a great idea.

    A variation on the theme is doing s clean install on your iDevice too.

    I did a clean install on my new iPhone 6 and went from multiple pages of unused apps to just two pages of apps I regularly use put into folders.

    Way cleaner, way better now.

  2. I just recently upgraded my iMac with an SSD to create a Fusion Drive. I had no choice but to do a clean install of the OS. And then I migrated my Time Machine backed up users accounts using the Migration Assistant. Seems to be the best route.

  3. Too bad Migration Assistant is as smart as a piece of toast. I finally gave up on it and now just keep things organized such that a full wipe and re-install only takes about half a day.

  4. Don’t risk using Migration Assistant if you want to keep up and running w/minimum glitches. Some things you installed in the past and then uninstalled may not have removed everything so some items may get “migrated” that you don’t want.

    Keep your old Mac running until the new Mac is humming along fine. I keep the old Mac around in case something bad happens early on and I need that access.

    There will be slowdowns getting all your apps and utilities up to date for the new Mac. Get that done and running fine before you bring in all your data.

    Take a serious look a security options on your new Mac, both in System Prefs and 3rd party.

    If you are willing to spend the bit of time to understand it, I’ld recommend Little Snitch, so you understand what is going on in the background. Without it, you might not know all the things going on with websites & phishing emails on the Internet.

  5. My new refurbished 2014 13″ MBA is waiting at the mailbox right now so I’ll be doing this very thing when I get home tonight. Like MDA said, space is at a premium so I have a 2GB external Mercury Elite Pro mini from OWC with my user files from my main machine. I’ll just be adding the programs I use most often along with my iTunes and iPhoto libraries stored on the external. Looking forward to starting “fresh.”

  6. i finally got the mac pro for which i’ve been yearning so long. i declined the migration thing just did firewire to thunderbolt target mode to copy what i wanted, exported bookmarks to html, export and import contacts, ical which i use a lot, mail folders. not quite as simple but i’d screwed with too, too much to just migrate all my screwwy things like double bookmark folders from a prior migration. i love love love this machine but i’m having a little learning curve with 10.10. don’t much like iTunes management or safari favorites and sidebar. also, don’t care for signing in so much. maybe, i don’t know how to manage everything quite yet and i’m a bit confused. but this machine, the elegance, the aesthetic. ohhh!, even the packaging took my breath away.

  7. I’ve become very efficient with clean installs over the years. I’ll say that the loss of Archive and Install has made things harder, but thanks to the App Store the process of rummaging for discs is truly over.

    Anyhow, my technique is to create a temporary drive partition for the OS X installer. Once I boot into it, I fire up the terminal and rename the Application, Library and Users folders. Everything else not in those folders (just system files in my case) gets the rm -r treatment. Finally I run the installer, delete its partition and move the files back.

    Of course that won’t help if you’ve got hard disk issues that need a reformat.

  8. This is an FYI… When beta-testing Yosemite, I found that I can use the built-in high-speed SD card slot for booting my Mac mini (2011). If the SDXC card is reasonably fast (mine is from Sony and described as “Class 10 – 40MB/s”), this works surprisingly well. It’s MUCH faster than a USB 2.0 startup disk, and it even felt a bit faster than booting Mavericks from my internal hard drive. It’s obviously not as fast as booting from a “real” internal SSD, but it worked out well for testing.

    This let me leave my internal drive alone, for testing. I reformatted the SD card for Mac (using the Partition tab in Disk Utility), with partition map scheme “GUID Partition Table” and format “Mac OS Extended (Journaled).” Then I ran a Yosemite CLEAN install targeting the SD card’s volume. No special steps needed.

    64GB SDXC cards are now less than $40. 32GB for less than $20 (64GB is better for this purpose). I now have mine set up with all of my disk maintenance utilities, and leave it in the SD card slot as a “Super Recovery HD.”

    1. Not quite “over a decade ago”; the first Mac Pro (Intel) was released in the second half of 2006. 😉 But that’s STILL a very long time…

      Your system accumulates a lot of “stuff” such as extensions and drivers (and other processes) that run during startup (and login), and many of them are for apps and hardware that you no longer use. And there are A LOT of “Application Support” and other Library files, taking up space on your startup disk for apps you may have installed “a decade ago,” many that you no longer use.

      A Mac Pro is fast, and you probably have more than typical RAM installed, so you may not see “symptoms” of performance issues. If you have a drive bay open, you should put an empty drive in there, do a clean install of Yosemite there, and see if you notice any difference.

  9. I upgraded the hard drive on my Mac Mini and decided a fresh install was needed. Having updated the OS several times, some things were off. The fresh install did help a bit but there are still some issues.
    I will probably need to do the same to my rMBP.
    Hardest bit with a fresh install is making sure you have backups of applications or installers that you used several years ago.

  10. Clean install is always the best option. I wish Apple would make it easier to do. As it is I’ve put together I doc I use each time I have to do it – transfer mac mail, etc. etc. etc.

  11. Every 2 or 3 OS’s (depending on the how the computer is acting) I do a clean install. First I make sure the OLD computer OS is up to date and run a Disk Verify to check the drive is in good health. I run a Permissions Repair, then I make a Time Machine backup. On the new computer all apps are reloaded fresh and updated making sure they are versions built for the new OS. (I always have an Admin side to any computer I set up—co-workers, home, friends, relatives or my own.) On the new computer run Disk Verify (you never know) run a Permissions Repair, up date the OS if needed, then transfer only the user sides using the Migration app in Utilities. Run Permissions repair after that transfer. i’ve had zero problems with this method.

  12. This is sheer nonsense. This hearkens back to the old adage ‘PC users work on their computers, Mac users work with their computers.”

    My current mac started life as a PowerMac 7200 in 1994 or so. I’ve simply updated all my macs since, to my current system which is a 2011 Mini. No problems.

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