Adobe Lightroom Classic aggressively builds a 100GB cache on macOS containing Apple system files

Adobe Lightroom Classic creates (and rebuilds when deleted) a 100GB cache with ≥10,000 files, many of them >100MB in size, containing Apple ML files, at  /Users/ [username] /Library/Caches/com.adobe.LightroomClassicCC7/com.apple.e5rt.e5bundlecache/, even without using ML-based features or any user interaction. When the user deletes this cache; it’s immediately rebuilt when starting Lightroom. This only seems to happen with one large catalog.

When I contacted Adobe support about this, they told me that I only have a “basic” Creative Cloud subscription and should just “buy more storage” (!). Absolutely unbelievable and obviously not helping.

Lightroom Classic Version: 15.6 (current)

OS Version: macOS 27.0.1 (current) on a 2021 M1 iMac (but the issue was already present in 26.*)

# Expected result

I have a mid-size Lightroom catalogue covering an archive with about 60,000 photos (170 GB). Both this catalogue and my images are on an external SSD. The Lightroom catalogue itself is about 700 MB; `Previews.lrdata` is 18.5 GB, which I believe is within parameters.

With this setup, Lightroom Classic should only create (and occasionally purge) a small cache on the system disk.

# Actual Result

I recently realized that a freshly installed system (clean macOS 26 install, all apps reinstalled from scratch, with a healthy 150 GB free space) only had 22 GB left for data, and even basic work with a few apps opened had noticeable latency. An analysis tool (DaisyDisk) showed that I only had 22 GB left, as Lightroom Classic created a massive 100 GB cache at

/Users/ [username] /Library/Caches/com.adobe.LightroomClassicCC7/com.apple.e5rt.e5bundlecache/26A434/

This cache contained > 10,000 folders, many of them exactly 100.4 MB in size, with long cryptic names such as

CDDD86E814753448EBBFA880AECFD1C984A4B80D83934B2BE27C52B2A98DC198

Each folder contained a .bundle file. “Show package contents” would reveal a `H13G.bundle` file, with the following content:

main
  main_mps_graph
    main_mps_graph.mpsgraphpackage
      manifest.plist
      original_model_0.mpsgraph
      resources.bin

I understand these are Apple machine learning system files used in AI functions.

Based on suggestions from several LLMs, I deleted that whole /26A434/ cache and emptied the trash.

When I restarted Lightroom Classic (without doing anything else), it immediately started rebuilding that cache at a high speed (15 GB/min).

I then …

- uninstalled Lightroom Classic
- made sure that there are no more Lightroom Classic preferences and caches at
  - ~/Library/Application Support/Adobe/
  - ~/Library/Caches/
  - ~/Library/Logs/Adobe/
  - ~/Library/Preferences/Adobe/Lightroom/
  - ~/Pictures/
- restarted the Mac and
- reinstalled Lightroom Classic from the Creative Cloud app.

After this purge, starting Lightroom first would create _no_ cache at ~/Library/Caches/com.adobe.LightroomClassicCC7/.

However, when I restarted with my main catalog, Lightroom Classic immediately started building its cache at ~/Library/Caches/com.adobe.LightroomClassicCC7/com.apple.e5rt.e5bundlecache/

Accordingly, it seems the cache buildup with the ML files is caused by something in the catalog. But I see no way to identify and correct the issue.

Please advise.