---
id: mac-storage-basics.how-do-i-clear-lightroom-previews
url: https://storagestudio.us/faq/mac-storage-basics/how-do-i-clear-lightroom-previews
category: "Mac storage basics"
subcategory: "Caches, logs and temporary files"
question: "Why is my Lightroom Classic catalog folder so big?"
alt_questions:
  - "lightroom previews lrdata huge"
  - "discard 1:1 previews"
  - "lightroom catalog size mac"
  - "lightroom cache mac storage"
  - "reduce lightroom previews"
short_answer: "Mostly the Previews.lrdata file. Discard 1:1 previews from Library → Previews, set them to auto-discard in Catalog Settings, and limit the Camera Raw cache."
tags: ["lightroom", "previews", "adobe"]
related: ["https://storagestudio.us/faq/mac-storage-basics/how-do-i-clear-adobe-premiere-media-cache"]
applies_to: "all"
last_reviewed: 2026-10-01
---

# Why is my Lightroom Classic catalog folder so big?

Mostly previews. Lightroom Classic keeps a **Previews.lrdata** file next to the catalog, and full-size (1:1) and Smart Previews can grow very large.

- **Library → Previews → Discard 1:1 Previews** for folders you're not editing.
- In **Catalog Settings → File Handling**, set 1:1 previews to be discarded automatically after a period.
- Lower the **Camera Raw cache** size in Lightroom's Performance settings.

The previews are rebuilt when needed; your photos and edits aren't affected.