If I buy a new hard drive and clone my original onto it (using Carbon Copy Cloner or something similar), will my computer function exactly the same as it did before? Will things like licensed programs not work properly? (I can't think of any reason they wouldn't, but you never know.)

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    One point. If you want a start-up disk, you have to have the proper formatting scheme on it, before you clone onto it. For 10.4 and later, use GUID Partition Table
    – GEdgar
    Feb 23, 2014 at 14:49

4 Answers 4


Yes. I swap out drives all the time... it's basically transparent on a Mac. I've even booted my MacBook Pro's drive on my wife's MacBook Pro and vice versa. It takes a minute longer to boot as it reconfigures itself but once it starts you can't even tell the difference.

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    do you have any Adobe apps on either machine? That's what I think someone would be most likely to run into trouble, given the number of product registration issues they've caused.
    – Dori
    Sep 19, 2010 at 6:32
  • Yes, PS on my wife's. No issues... it was originally installed on her old mbp too. Sep 19, 2010 at 6:58
  • Is there a detailed step-by-step on how to do this ? thanks May 2, 2022 at 17:41

Short answer: Probably

Long answer:

Technically speaking CCC and similiar tools do not make bitwise exact copies of volumes. There are detectable differences (for example, each disk will have different UUIDs). Having said that, I have never seen any software that depends on something like the disk UUID, but it is possible someone uses it as a part of a copy protection scheme or something.

One exception is Time Machine. Time Machine uses the UUID to identify the source disk. So in order for time machine to incrementally continue on your previous backup, you'll have to use the command sudo tmutil associatedisk -a.

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    Time Machine depends on UUID. A solution to this problem is given here: hints.macworld.com/article.php?story=20090213071015789
    – mouviciel
    Sep 19, 2010 at 18:46
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    I never had problems even with time machine. I swapped out drives and when I hooked it up it picked up right where it left off. Maybe this is only an issue in Leopard? Sep 19, 2010 at 22:51
  • @Robert: Strange - my timemachine wanted to back up everything again. Once I changed the UUID to match the original all was fine.
    – n1000
    Feb 23, 2014 at 10:43

As has been said, everything should work. It is easy to test this. Simply put the drive in an external enclosure, clone the current drive, then use Startup Disk utility in System Preferences to boot off of the new disk. This will allow you to verify that everything works as intended. If your original disk is mounted, you probably want to eject it to ensure the system is picking anything up off of that disk.

  • +1... this is how I always test a drive that I'm swapping in. Sep 20, 2010 at 16:07

Yes, everything will work the same if you use software such as Carbon Copy Cloner and choose to move the entire hard disk to the new (or "other") one.

It is a great way to have a backup disk that will just work immediately in case if failure of the internal drive (this is how I do with my MacBook Pro), and it's a good companion (not substitute) of Time Machine.

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