InkskyIf you’ve ever browsed your Kindle’s documents folder, you’ve seen them: .sdr folders everywhere. Each ebook on your Kindle generates one, storing bookmarks, reading position, and annotations. When you delete a book, the sdr folder often stays behind — and over time, these orphans pile up into hundreds of useless files.
sdr-Cleaner is a free tool that finds and removes orphaned sdr folders automatically. It’s simple, safe, and takes about 5 seconds to run.
What sdr folders actually are
Every ebook on your Kindle creates a companion folder named after the book’s ASIN or filename, ending in .sdr. Inside are tiny files that track:
- Your current reading position
- Bookmarks and highlights
- Annotations and notes
- Last page read
When you delete a book properly from your Kindle’s interface, the sdr folder goes with it. But if you delete books via USB, use Calibre to manage your library, or restore from backups, orphaned sdr folders accumulate. They don’t hurt anything, but they clutter your file system and take up space.
How sdr-Cleaner works
The tool scans your Kindle’s documents folder and compares every sdr folder against your actual ebook files. If the sdr folder doesn’t match any existing book, it gets deleted. If there IS a matching book, it stays — your reading progress is safe.
This comparison-based approach is what makes sdr-Cleaner safe. It never deletes anything that’s still in use.
Using sdr-Cleaner
- Connect your Kindle to your computer via USB
- Download sdr-Cleaner from BookFere
- Launch the tool — it auto-detects your Kindle drive
- Click “Clean” and wait a few seconds
- Done
The tool shows a count of how many orphaned folders it found before deleting, so you know exactly what’s happening. After cleaning, your Kindle’s storage is a little tidier — and you didn’t have to manually sort through hundreds of folders.
This is a maintenance tool you can run once every few months. It’s especially useful after a big library reorganization in Calibre.