Many think that a file’s type is determined by its extension. Although partly true, that’s indirect: it’s the UTI which sets the type, as explained here.
UTIutility
Explore UTIs, MIME and file types, extensions, and more. Now runs native on Intel and Apple Silicon Macs.
You’re checking through old files. How can you tell which file type they are when you don’t recognise the extension, or they don’t even have that to help?
What’s a UUID, and a UTI? What can you learn from each, and where can you look them up? Important info about these, and a new release of a tool to help.
This page is for your support questions and comments on my free app UTIutility, a live reference on […]
Later this year, in macOS 10.15, one of the media types which will become unsupported is JPEG 2000 still images. Here’s how to find and convert your old images.
You try to open a document – in this case, one of Firefox’s bookmarks – and nothing happens. What could be wrong? It turns out it’s a bug, of course. But where?
An old bug in UTIs can cause problems for apps, and may even crash them. The issue is that macOS can’t always tell what type of object certain ‘files’ are.
Each now built with the latest version of Xcode, and notarized for your added security. Recommended for Mojave users in particular.
How does macOS open the document that you double-click/tap? First of 3 parts explaining what should happen and where it can go wrong.
The Eclectic Light Company 