disk-utilityssdstartup
In the process of upgrading to a new SSD in my iMac 2017 Catalina. After setting everything up using Disk Utility, it is asking if I want to restore from “iMacintosh HD” or “Macintosh HD – Data” I read here of someone having a similar question but his situation was slightly different. I simply want to clone my existing startup disk so I can swap out the old drive with the new one. Can anyone guide me through this?
Many thanks in advance.
-JJ
The problem you are experiencing is because you only replaced the 1TB spinning portion of the Fusion drive; the 128GB SSD is still there with the boot partition on it.
You've confirmed this when you said that you can see both the Samsung SSD and the original HD. What you need to do now is wipe both and create a new Fusion drive to combine the 128GB SSD and the 1TB SSD into one CoreStorage volume.
I've detailed these steps in this post on how to do this. Since you've got everything backed up with Time Machine and are using it for recovery, you should have no problems migrating your data over.
Both the Disk Utility application and diskutil command do not allow free space to be converted to a new partition. Instead, you are suppose to create new partitions by splitting an existing partition.
So first of all, enter the command given below to reclaim the free space to the existing APFS partition.
diskutil apfs resizecontainer disk0s2 0
Open the Disk Utility application and highlight the container disk1, then click on the Partition button. You should get an image similar to what is shown below.
Next, click on the Partition button in the popup window. You should get an image similar to what is shown below.
Click on the +button, then enter a name. I chose Macintosh HD 2. Make sure the format is APFS and the size is 350 GB. The result should be an image similar to what is shown below.
Next, click on the Apply button. You should get an image similar to what is shown below.
Next, click on the Partition button in the popup window. The result should be an image similar to what is shown below.
Note: The Disk Utility application may show incorrect results. You may need to quit and reopen the Disk Utility application to see the correct results.
Best Answer
Cloning isn’t easy in my experience since you need to first learn a bit about specifics and how to select a proper clone tool tool and understand any filesystem differences between your exact versions of OS.
Why not install a fresh OS on the SSD and then when it first starts migrate everything from the old OS?
Apple tools handle this for you including all the version difference if you choose a different OS on the new disk. And with two disks, you can thoroughly test the new drive before you install it or wipe the internal drive.