The bar chart in Storage Settings shows most of your startup volume is full of System Data. What does it mean, and what use is it? Is its measure of used and free space accurate?
Disk Utility
You’re in a rush to eject an external disk, but the Finder tells you it’s in use by unnamed apps. What should you do next, and what has Sloth to do with it?
How snapshots are created from a volume in around 0.01 second, why they will grow in size over time, how they can only be of complete volumes, and can’t be edited.
What separates System and Data volumes, and how does macOS know they’re part of a boot volume group? What distinguished backup volumes, and what is Sidecar?
How to tell whether someone has been eating the (APFS) porridge on one of your disks, using Get Info and DiskUtility’s First Aid. And a surprise hidden volume from 3 years ago.
Which are the best tools for the occasional user? For someone who creates disk images to distribute sofware? Or for hacking sparse bundles?
Focussing on sparse bundles and UDIF read-write disk images, this explains their types, structure, how their size can change, and how fast they are in use.
APFS or HFS+? Which can Time Machine back up to? What about hard disks? Which format for use on PCs? And which are supported by Disk Utility now?
What if you want to boot your Mac using two or more different versions of macOS, with different versions of APFS? Here’s how to avoid problems.
Originally two separate apps, they were brought together in Mac OS X, and have survived largely unscathed to Sequoia. Here are some highs and lows to remember.
The Eclectic Light Company 