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70 Points

Sun, Dec 9, 2018 9:33 PM

Lightroom Classic 8.0: Large Sized Catalog Files

I found it very difficult to find information on the bug I am having across multiple machines with Lightroom CC Classic after the latest update but have found a thread that demonstrates and shows exactly what I am seeing.

Lightroom Classic CC 8.0 large sized backups and LRCAT file

If I open any older catalog that is of reasonable size, as soon as I close LR the file size shoots up to nearly 200mb. I deal with many LR catalogs each day and download/upload and this is crippling my work flow.

This is a very big bug and frustrating as a user, any proposed work arounds until the bug is fixed?


Adobe Administrator


8.2K Messages


118.2K Points

2 years ago

I see you've had an official response from @Simon Chen on the other forum: cross-linking here for reference:

"Checked the catalog, seeing that the 3D color LUT took up the majority of the size of the new catalog. The catalog stores a total of 1021 entries of custom 3D LUT (not from Adobe), presumably coming from some custom camera profiles/presets.

Lightroom caches unique 3D LUT both in the catalog and on the disk to facilitate transportation of catalogs among different machines and quick access to them at develop time. Lightroom does not keep a copy of the 3D LUT at each history step.

The catalog size increase for a newly created/exported catalog is a manifestation of this. It was introduced as part of the Lightroom Classic 7.3.

Given that a reference to a 3D LUT could be buried in one of a history step (customer can go back in the history step to reference a 3D LUT at any time). Lightroom catalog does not currently have an infrastructure to do proper reference counting of custom 3D LUT usage. So it just includes a copy of every custom 3D LUT ever used.

 We have to consider this case of multiple catalog usage scenario and see if we can optimize it. Thanks for the report.

 P.S. The 3D LUT is also cached locally on disk at "~/Library/Application Support/Adobe/CameraRaw/Tables" on macOS. There is a similar Window directory location."


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