Two command tools, lsregister and lsappinfo, are often recommended for dealing with LaunchServices problems. This summarises what they can and cannot do.
Finder
How macOS makes the association between file types and apps for the Finder and GUI, using UTIs and their associated data including filename extensions. Why clashes occur, and how they’re resolved.
When you double-click a file and expect to see it opened by the app of your choice, but instead it’s opened by the wrong app, or the wrong version of the right app, or maybe macOS refuses to open it at all. How to fix that.
When listing files by name, should 20test.text come before or after 200test.text? Which order is the more ‘natural’? How this quickly becomes complex.
Many document formats store metadata with their data. Choosing the right ones to use must ensure their access, indexing and search. Here’s how to check those, and why Keywords are usually a good choice.
A new drag-and-drop app to change quarantine extended attributes on documents, so enabling you to double-click them to open when they won’t otherwise.
How this expresses file sizes, which data it includes, the difference between KB and KiB, how to view more of a file’s metadata, and more.
How to find and use the Finder’s Get Info sibling, the Inspector, how to make exact duplicates, a free slideshow without Keynote, and an Easter Egg.
How to use the Finder’s Lock feature, and as the Immutable flag in Terminal. What its effects are, and how well it’s retained. How iCloud Drive can’t cope with it, and how you can use it in your own lightweight versioning system.
Soon after introducing iCloud and iCloud Drive, Apple changed the way most metadata was handled to ensure it was synced up to the cloud. Recently this has been reversed, and little metadata is now synced. Was this an accident or intentional? What is the workaround?
The Eclectic Light Company 