HOW TO Back up your Data volume

1 Set the destination

Connect the external drive on which you’re going to store the backup. If necessary, format it in APFS using Disk Utility. Then open the Time Machine pane, click the Select Disk button and choose your external drive.

2 Set exclusions

Click the Options button to exclude any items from the backup. Consider adding huge Photos libraries, virtual machines, and massive apps like Xcode, which could make backing up take hours or even days to complete.

3 First full backup

In a couple of minutes, Time Machine will make its first and full backup of your Data volume. It takes a long time to prepare, but once it gets going, backing up to APFS is quick if you’ve excluded problem items.

4 Copy the Data volume

In Carbon Copy Cloner, create a new task with the task list icon and name it. Add the volume you’re upgrading, typically Macintosh HD, as the Source, then the Destination volume. Click Start.

5 Set excluded items

Click Task Filter at the bottom of the main window to select items you don’t want included in the copy. Consider keeping separate copies of huge files like virtual machines which change constantly when in use.

6 Preview or Compare

Before copying, click on the Preview tool at the top for a full dry run if you want. When the copy is done, click on the Compare tool if you want to verify that every file has been copied across into your clone.