Inksky
You’ve just sideloaded 50 books onto your e-reader and suddenly the device is sluggish, the battery is draining fast, and page turns lag by a full second. The culprit is almost certainly stuck indexing — and the fix is simpler than you might think.
Why does indexing slow everything down?
When you add books to a Kindle, the device scans and indexes each one to make the full-text search work. Indexing is CPU-intensive: the processor has to parse every word in every book and build a searchable index. A dozen books takes a few minutes. A few hundred can take hours, or longer if any file contains errors the indexer can’t handle. During this process, the Kindle runs at full power — no sleep, no low-power states — so battery drain is dramatically higher and interface responsiveness suffers.
Kobo devices don’t do full-text indexing, so they don’t have this specific problem. If your Kobo is slow after adding books, the cause is more likely a database issue or a corrupted EPUB, covered in our Kobo database repair guide.
How to check for stuck indexing on Kindle
From your Kindle’s home screen, search for a nonsense word like “zzzzzz” or “qwertyuiop.” If the search results show “Text in Books” with items listed under “Items not yet indexed,” tap it. You’ll see exactly which books are stuck in the indexing queue. A stuck book will often show at the top of the list and stay there for hours or days — the indexer keeps retrying the problematic file in a loop.
Fixing stuck books
For each stuck book, the process is straightforward:
- Delete it from the Kindle — long-press the cover and select “Remove Download.”
- Re-process the file in Calibre — use the “Polish Books” tool or convert the book from EPUB to EPUB (or AZW3 to AZW3). This often fixes encoding errors, invalid markup, or embedded fonts that confuse the Kindle indexer.
- Re-sideload the book — send it back via USB or Send to Kindle.
If a specific book keeps getting stuck after multiple attempts, check whether it contains DRM. DRM-protected books from sources other than Amazon won’t index on a Kindle, which is expected behavior — you need to remove the DRM first using Calibre with the DeDRM plugin (for books you legally own and are converting for personal use).
Prevention
When sideloading large batches, add books in groups of 20–30 rather than all at once. Let each batch finish indexing (monitor via the search trick above) before adding the next. Also, run new books through Calibre’s “Check” tool (right-click → Edit Book → Check Book) before sideloading — it catches XML errors, missing closing tags, and broken font references that cause indexing failures.
If your Kindle is actively indexing a large batch, leave it plugged in and connected to Wi-Fi overnight. The indexer runs fastest when the device is charging, and Wi-Fi allows it to pull any missing metadata from Amazon’s servers that might resolve indexing ambiguities.