How to clone a Mac.


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Jul 16, 2021
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Lory wrote an article back on the 18th of March '20 called Back it Up. I'm not aloud to comment on it since it was posted over a year ago but I'm wondering if someone wouldn't mind seeing ifthey could help with an issue I was having.

I have followed the directions to the T. The final step where you click Clone I get an error message and that it needs to Convert to APFS. I click on convert and it says SuperDuper cannot automatically make my SSD macOS 10.15.5 ready. This could be due to a number of reasons, including using the wrong partition scheme (non-GUID), HFS+ encryption or Time Machine backups on the volume. To copy macOS you'll need to reformat the drive.

I originally reformatted per the instructions but my computer didn't give me an option to choose a scheme, I didn't encrypt it and I don't have Time Machine backups. Would you be able help me figure how to get around this so I can complete the cloning process.



Mar 10, 2012
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Hi lotuska,

First of all, welcome to the iMore Forums. :)

Let's first check the partition scheme that your external drive is using.
The easiest way, but not the only way, to do so is:
  1. Click on the  menu in the top left of your screen.
  2. While having the Option (⌥) key pressed, choose System Information…
    Note: System Information… will not appear unless the Option key is pressed.
  3. ​In the System Information window, select USB in the left sidebar.
    This will list all the USB devices connected to your computer - including internal like the FaceTime camera if your computer has one.
    Screen Shot 2021-07-17 at 05.17.30.png

    If you use another kind of drive like Thunderbolt, select that instead ;)
  4. Go through the different devices until you see one that lists your drive's name. Then look at the line that says Partition Map Type, that's the partition scheme.

    In my screenshot (highlighted), that is GPT (GUID Partition Table which is what Intel and I believe Apple Silicon Mac computers require to start - and what is used on all new Windows computers as well.
    Screen Shot 2021-07-17 at 05.20.25.png
Partition schemes can be changed, but it does require erasing the entire drive, since they determine how the volumes are written on the drive itself.

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