Photo Workflow Cleanup: Lightroom Cache and RAW Libraries

Where Lightroom hides the gigabytes

Lightroom keeps four classes of files next to your work, and none of them are the photographs themselves. Knowing which is which is the difference between a safe cleanup and a ruined catalog, so start by naming them.

• Camera Raw cache — %LOCALAPPDATA%\Adobe\CameraRaw; stores decoded RAW data, safe to purge from Lightroom preferences
• Previews — the [catalog] Previews.lrdata folder next to your .lrcat file; regenerates on demand and grows with every browse
• Smart Previews — [catalog] Smart Previews.lrdata; only needed while the originals are offline
• Catalog backups — the Backups folder beside the catalog: one zipped .lrcat per week, forever, until you intervene
• Video files and 1:1 preview caches for clips you watched once and never edited

Safe to delete, safe to shrink, never touch

Previews and Smart Previews are derived data: delete them and Lightroom rebuilds what it needs. Browsing is slower on the first pass through each folder, and nothing else changes — that is the whole cost. Catalog backups deserve a retention rule rather than a purge: keep the last four plus the one before any major restructure, and bin the rest.

The .lrcat file itself is your edits, keywords and history — never a cleanup target. If the catalog is gigabytes, the fix is clearing old development history or finishing abandoned imports, not deleting the database you actually work in.

Keeping the workflow lean

Set a hard cap on the Camera Raw cache in the performance section of Lightroom Classic preferences, and let the app enforce it instead of you. Keep catalogs and previews on the fastest internal disk, archive finished years to cold storage, and once a quarter open the Backups folder and apply the retention rule. That is the entire maintenance plan, and it fits on a sticky note.

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