If generating QuickLook thumbnails and previews, and indexing metadata for Spotlight, depend on UTIs, how come they tolerate misleading file extensions? A simple practical demo.
UTIutility
How to discover what went wrong when a document doesn’t show the right thumbnail, but a generic icon instead. How to dive deeper to solve problems with 3rd party thumbnail and preview generators.
For the last 10 years, macOS has relied on Uniform Type Identifiers to recognise different types of files, for opening in apps, QuickLook, Spotlight and in other features.
Four little utilities now compatible with macOS Tahoes, covering repair of Finder aliases, creating test sparse files and checking special file types, looking up UTI types, and analysing language.
How to discover which QuickLook generator or app extension should be creating Thumbnails or Previews for different file types, using this new version of Mints.
Details of the chain of information, from the UTI of the file to be opened, through LaunchServices’ database of document types. How to deal with problems.
For working with document versions, managing sparse bundles, benchmarking disk performance, checking TCC privacy protection, and looking up UTIs.
How does the Finder know the right app to open a file with? Or QuickLook how to preview its contents? Or other services like Spotlight know how to index and handle files? UTIs.
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.
Explore UTIs, MIME and file types, extensions, and more. Now runs native on Intel and Apple Silicon Macs.
The Eclectic Light Company 