How to stop Finder from triggering full file download of a file on network share to generate the thumbnail

Default behaviour of the macOS when interacting via Finder with a network share is to create thumbnails to provide a nice user experience. This behaviour is implemented by QuickLook framework.

This triggers the full file download and quickly lead to cache using large disk space and even cache trashing.

We can disable QuickLook selectively by injecting specially prepared .DS_Store file with instruction/setup to disable thumbnails in that directory but still degrades user's experience only in the network share ecosystem.

Is there any way we can provide our own thumbnails or ask Finder to not download full file to generate the thumbnail?

Is there any way we can provide our own thumbnails or ask Finder to not download full file to generate the thumbnail?

Depending on exactly what you need, I can think of two options:

  1. If you're dealing with your own apps files, then you can use a Thumbnail Extension to provide your own thumbnails.

  2. If you're dealing with something "specific" (server, your own service, etc), then you could use the file provider architecture to act as a "front end" to the network share. At that point the actual download process is controlled by your provider (not the Finder), so you can do "whatever" you want.

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Kevin Elliott
DTS Engineer, CoreOS/Hardware

How to stop Finder from triggering full file download of a file on network share to generate the thumbnail
 
 
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