What you need to know about the APFS file system, its containers and volumes, so you can understand errors and how to repair them.
Disk Utility
What you need to know about the HFS+ file system, so you can understand error reports and how to repair it using Disk Utility and other tools.
What you need to know about disk formatting using the GUID Partition Table (GPT) to understand its problems and how to repair it.
Apple says that if you run First Aid on a disk, each of its volumes is checked too. Is that really true?
Disk Utility can’t image APFS volumes, and normally returns an error if you try to image a container. Here’s the workaround.
If something goes wrong with Catalina’s boot Volume Group, it seems there’s no way to repair it, or change the Data volume. Or is there?
Older versions of Catalina can fail to erase the System and Data volumes, but 10.15.6 should be able to, making clean re-installation simpler.
Trying to discover the effective size of a snapshot proves baffling, particularly when the Finder claims it’s almost astronomical.
Updating Big Sur can cause the storage required by the system to double in size. Snapshots appear to be the cause. What’s the solution?
What do you know about the hidden and unmounted EFI partition on all the disks you use with your Mac? It could be very important.
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