Can I run a mac entirely off an external hard drive?

Discussion in 'Mac Basics and Help' started by yalag, Apr 3, 2018.

  1. yalag macrumors 65816

    Joined:
    Nov 18, 2007
    #1
    My 2015 mac mini recently died (or at least got very slow), I suspect the spinning drive is dying. I'd rather not spend another thousand or more on a new mac mini at this point. Can I just attach an external hard drive and always boot from there? I 'm only using it as a download machine anyway, with no monitor attached.
     
  2. Spyderweb122 macrumors newbie

    Joined:
    Aug 14, 2014
    Location:
    Manitoba, Canada
    #2
    Should be possible. I've booted from USB connected hard drives on my 2008 MacBook.
     
  3. DeltaMac macrumors G3

    DeltaMac

    Joined:
    Jul 30, 2003
    Location:
    Delaware
    #3
    Yes, you can have everything installed, and boot from an external hard drive. You would have the choice of either USB 3.0 or a Thunderbolt external drive. The TB will be somewhat more expensive, and the additional speed may not necessarily be worth the money to go Thunderbolt.
    You might have to go inside and disconnect the internal hard drive. Those sometimes fail badly enough to interfere with the rest of the system.
    This can also be a good time to go to an SSD, which will give you a very noticeable increase in speed and responsiveness of your system. Best plan would be to change out the internal for an SSD, but also understand not wanting to do "surgery" on your mini. :cool: An SSD in an external USB 3.0 enclosure would be a Good Thing™
     
  4. yalag thread starter macrumors 65816

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    Nov 18, 2007
    #4
    Do you happen to know if my mac mini has usb 3.0?
     
  5. nebo1ss macrumors 68030

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    Jun 2, 2010
    #5
    My 2012 has USB 3 would be surprised if your 2015 did not.
     
  6. yalag thread starter macrumors 65816

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    Nov 18, 2007
    #6
    good news, thanks! Do you know if usb3 is going to be sufficient for running the mac smoothly? I never thought you could run an OS without glitches directly from an external drive
     
  7. DeltaMac macrumors G3

    DeltaMac

    Joined:
    Jul 30, 2003
    Location:
    Delaware
    #7
    Yes, assuming your mini was new in 2015 (which makes it a Late 2014 mini)
    All current new minis are Late 2014 models.

    Even if yours was a 2011 or older mini, USB 2.0 would still give you a usable system, particularly if you change to an SSD, just not the same leap that you would get with an SSD and USB 3.0
    --- Post Merged, Apr 3, 2018 ---
    You would be fine with USB 3.0
    Will that be equal to an internal drive? No.
    Will it necessarily be noticeable to you? Probably not... :D
     
  8. Longkeg macrumors regular

    Joined:
    Jul 18, 2014
    Location:
    S. Florida
    #8
    What makes you think the drive is dying? The reason I ask is my sister's mini (same year) was behaving exactly as you describe. Took it to Apple and they gave the drive a clean bill of health... "the OS must be corrupted" they said. I took it home and did a Time Machine restore, erasing the drive before the restoration. Four hours later I fire it up only to find no change. Then I wiped and reformatted the drive and did a clean, new installation and it was like a new machine. By all means get the external and proceed with your project. You have nothing to loose. But don't give up on the internal drive until you have tried reformatting it in Disk Utility.
     
  9. Fishrrman macrumors P6

    Fishrrman

    Joined:
    Feb 20, 2009
    #9
    The OP asked:
    "Can I run a mac entirely off an external hard drive?"

    Yes.
    Of course you can.
    This is child's play on a Mac.

    I've been booting and running my late 2012 Mac Mini from an SSD (in a USB3/SATA dock) since the first day I took it out of the box in January 2013. Still runs great.

    Get either a "ready-to-go" USB3 SSD such as this:
    http://www.amazon.com/exec/obidos/ASIN/B00ZTRY532?tag=delt-20

    or...

    Get a "bare" SATA SSD and either a USB3 enclosure (make sure it supports UASP), or a USB/SATA dock, or even a USB3/SATA adapter dongle like this:
    https://www.amazon.com/Sabrent-2-5-...478&sr=1-2-spell&keywords=sabremt+usb3+to+ssd

    Then, set up the SSD with the OS, applications, and your "basic" accounts.
    By "basic", I mean leave large libraries of movies, music and pictures on another drive (they don't need speed).

    The Mini will run much better.
    If the original drive inside was a platter-based HDD, you won't believe the increase in performance until you try it.
    It will run far, FAR BETTER THAN NEW.

    Hmmm... as others mentioned above...
    What makes you think the drive has failed?
    What happens (exactly) after you press the power on button?
     
  10. dwig macrumors 6502a

    Joined:
    Jan 4, 2015
    Location:
    Key West FL
    #10
    I use SuperDuper to clone my insternal drive to an external as a backup. CarbonCopyCloner is another popular tool for this, though you can simply do a manual new OS install on a mounted external drive as well. For me, the external sits on a shelf for use only in "emergencies" should the internal fail. For that reason, I use a cloner monthly to update the external.

    I can easily boot from either drive by holding the OPTION key during boot. This will case the Mac to display a list of all bootable drives and let you choose. You can select the default used when booting w/o OPTION using the Startup Disk module in System Preferences. No matter which you boot from, all drives will be visible, provided they are working properly.

    If you think your internal drive is failing, getting an external as a backup is highly advised. Keep in mind that performance will be largely controlled by the speed of the interface to the external drive, with drive speed a secondary concern. It will be extremely slow and sluggish with USB2. USB3 will be a bit slow booting but generally fine once running, and Thunderbolt even better. Using a SSD instead of a HD will help a lot.
     
  11. vertical smile macrumors 68040

    vertical smile

    Joined:
    Sep 23, 2014
    #11
    Yes, I have been doing this for years.

    I have even booted Macs from a few different iPods before. Anyone else try this?

    Longkeg could be correct, and I would back up the drive, and do a wipe and reinstall before investing in something, unless you want to upgrade to a SSD, which I would recommend.

    I will warn about the Apple Store's HW diagnostic tool. It kept passing my Late 2012 iMac with a Fusion drive that had very obvious drive issues. They kept suggesting that the system was corrupted, do a wipe, only to have the issue come back a few months, then weeks, then days later, until it finally totally broke and wouldn't boot into anything, including recovery, or their HW diagnostic tool.


    Good tip, I do the same thing.

    Although, I have two external HDDs that I alternate backing up my boot drives before upgrading to a new MacOS. This is good for troubleshooting, and nice if you upgrade then find out you hate the new OS. I wish iOS was this way.
     
  12. dwig macrumors 6502a

    Joined:
    Jan 4, 2015
    Location:
    Key West FL
    #12
    I don't keep any important data on my internal drive. It is used for the OS, apps, and short term temp storage. That way, having one large external partitioned into multiple partitions that match my internal SSD's size (1Tb) is "good enough". I have nearly 8Tb (and growing!) of data files (mostly photos) stored on the external drives. These get monthly backups to an alternating A & B set, A at the end of odd numbered months and B after the evens. That way I don't have to destroy my only backup while a new one and I have the older set to fall back to if I need a restore and the newest set has issues.
     
  13. vertical smile macrumors 68040

    vertical smile

    Joined:
    Sep 23, 2014
    #13
    Yea, I forgot to mentioned that the two external HDDs, have many partitions on them. When it comes time to clone the boot drive, I just choose one of the empty partitions.

    So, it is a drive with multiple boot partitions.

    The reason why I use two, was because I was worried that something would happen to one of them and I didn't want to lose all my backups, plus the drives wouldn't run out of partitions as fast.
     

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