Next, open the Time Machine pane, and click on Select Disk to tell Time Machine to use your new volume for backups. If that happens, simply try again, or try unmounting any existing volumes on the disk first. Occasionally, Disk Utility can still return an error claiming that it was unable to unmount the disk properly, so couldn’t format it.

If you then wish to check that your new disk and its formatting are correct, you can run First Aid on both the disk and container. That is the standard combination of settings for unencrypted APFS format external disks. In the settings, select Scheme: GUID Partition Map, and Format: APFS, although the latter will be changed later by Time Machine. Select the disk in the list at the left then click on the Erase tool to format it. In this case, it was important as I needed to format the disk, which had previously contained backups from another Apple Silicon Mac.Ĭonnect your external backup disk, and once it has mounted open Disk Utility. You don’t have to prepare an APFS volume, as Time Machine will do that for you, but I prefer to make one ready using Disk Utility. If you’re still waiting to decide when to upgrade, this could help make your mind up. This article shows how you can set this up and solve one problem which can occur. For many of those who upgraded to Catalina, only to suffer protracted problems with Time Machine backing up to its traditional HFS+ destinations, this is one good reason to upgrade early.

One of Big Sur’s biggest attractions is that it can now make Time Machine backups to APFS volumes.

Turning on time machine for mac