ThreadView file guide
How to create embroidery file thumbnails in Finder
Finder does not natively understand every embroidery format. A Quick Look thumbnail extension can render a safe preview while leaving the original machine file untouched.
Install a viewer with a thumbnail extension
Move the notarized app to Applications and open it once so macOS can register its embedded Quick Look extension.
Use a supported file extension
The viewer must declare the formats it understands. ThreadView registers DST, PES, JEF and EXP files under its embroidery content type.
Allow Finder to refresh
Switch views or reopen the folder after installation. macOS controls thumbnail caching, so previously cached generic icons may take a moment to update.
Open the full audit when needed
A thumbnail is for recognition, not production approval. Open the design in the app to check dimensions, stitches, colors and compatibility.