Guide

Data & Storage

May 15, 2026

Understand what Kestrel stores, how much space it uses, and how to delete data.

The Key Point: Kestrel stores its analysis data in a hidden .kestrel folder inside every folder you analyze. Your original photos are never touched. You can delete the .kestrel folder anytime to free up space.

What's in the .kestrel folder?

Main analysis database

File: kestrel_database.csv

This is the heart of Kestrel's analysis. It contains:

  • Quality scores for every photo
  • Scene assignments (which photos are grouped together)
  • Species and family classifications
  • Any ratings or decisions you made

Thumbnail crops & previews

Folder: culling_TMP/

This folder contains:

  • Full-resolution RAW previews — extracted from RAW files so Kestrel can display them quickly in the UI. This can use significant space for large image libraries.
  • Temporary files and caches

Want to save disk space?

Open Kestrel Settings → "Data & Preview" → disable "Cache RAW Preview Images". This prevents the large preview cache from being created. Kestrel will still work, but RAW images may load a bit slower in the UI.

How much space does .kestrel use?

The .kestrel folder uses approximately 1 MB of additional space per 100 MB of photos (on average). The exact amount depends on:

  • Number of photos
  • Photo resolution and file size
  • Whether RAW preview caching is enabled

Example: A 50 GB photo library would add roughly 500 MB of Kestrel data (assuming preview caching is on).

Deleting Kestrel data

Using Kestrel (recommended)

This is the easiest way to clean up analysis data:

How to clear analysis data:

  1. Open the analyzed folder in Kestrel
  2. In the folder tree on the left, right-click the folder name
  3. Select "Clear Kestrel Data"
  4. Confirm — the analysis data will be deleted and disk space freed

Important: This only deletes Kestrel's analysis. Your photos are completely safe. You can re-analyze the folder anytime.

Manual deletion (for advanced users)

If you prefer to delete manually:

On Windows:

  1. Open the folder containing your analyzed photos in File Explorer
  2. Show hidden files: Click View → check "Hidden items"
  3. Look for the .kestrel folder
  4. Right-click → Delete

On macOS:

Option 1: Using Finder (easier)

  1. Open Finder
  2. Press Cmd+Shift+. (period) to show hidden files
  3. Navigate to your photo folder
  4. Find the .kestrel folder and drag it to Trash

Option 2: Using Terminal

For advanced users, you can use the terminal:

rm -rf /path/to/your/folder/.kestrel

Replace /path/to/your/folder with your actual folder path.

Why delete analysis data? You might want to delete it to free up disk space, or to have Kestrel re-analyze with different settings (e.g., a lower detection threshold). Simply delete the data and re-analyze — Kestrel will rebuild everything from scratch.