How to put your Mac into Safe mode, what Apple claims it does, and what evidence there is of its benefits. Includes an assessment of free space it may create.
Disk Utility
The Finder’s Get Info figures allow for sparse files when giving size ‘on disk’, but don’t take into account shared data in clone files. This can prove misleading, as shown here with VMs.
Snapshots made by Time Machine and tmutil should be purgeable, although sometimes they won’t purge, and aren’t shown reliably as purgeable space. An exploration of bugs and missing documentation.
When you First Aid in Disk Utility, or an equivalent command tool, it reports the formatting and modification details of each volume. Here’s how to interpret them, with details of all versions of APFS and when they were released.
Demonstrated 10 years ago as a major new feature in APFS, and capable of blazingly fast rollback preserving data including document versions, snapshots still aren’t fully accessible or documented.
When trouble strikes a disk image, macOS normally refuses to accept and mount it. This details how to use hdiutil to attach the image as a device so it can be repaired by fsck_apfs.
The new ASIF disk image type is now 18 months old. How well does it perform? Is it as good as claimed? It all depends on whether you want to use encryption.
They come in a multitude of formats and variants, and are used throughout macOS and apps. How do you use them, and what should be wary of?
Should you attempt a repair in Recovery mode? Is it just a warning? How to identify the file or folder with a problem, and what to do to fix or prevent it from recurring.
Safe mode is claimed to do 3 things: block 3rd party extensions, clear caches, and check your startup disk. But what disk checks does it really make, and how are they different?
The Eclectic Light Company 