Cloning Mac disk using external enclosure and Disk Utility

We got a ssd upgrade for a Mac (JetDrive 885) which comes with an enclosure to allow data to be copied to the new drive. This can be done with Disk Utility – as you are cloning the boot drive you need to run this in recovery mode (boot holding cmd – r). Presumably booting from a usb stick would work as well.

Once in disk utility choose the external drive, select Restore and choose to restore from the Macintosh HD. At this point we ran into an issue:

Could not change the partition type for /dev/disk1s1 - error -5342

We eventually found the problem Рthe new ssd had been configured with a MBR partition table, not GPT. To fix this go to the View menu and choose Show All Devices. Then select the external device at the top level and click erase. This should allow you to choose MBR or GPT partition schemes.

Published by

Jamie Scott

IT Administrator at the Institute for Gravitational Research, University of Glasgow