Encountered the error: database disk image is malformed

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When syncing with the connected Kindle by clicking on the connection icon or pressing shortcut F2, in some rare cases Kindle Mate might encounter the unhandled exception with the message ‘database disk image is malformed’.   And this exception will prevent you from auto-syncing after that. You can still manually import your Kindle clippings separately, since this error is only related to vocabulary builder file.



This error occurs when the Kindle Vocabulary Builder database file (vocab.db) in Kindle device, which is a Sqlite database, somehow gets corrupted.   There are many reasons that a sqlite db may get corrupted, such as aged Kindles, power outage, hardware issues, check the https://sqlite.org/faq.html#q21 for more details.

Besides the above causes, when using Kindle Mate this exception might occur AFTER you have done one or more Sync Changes Back to Kindle, with the option of sync vocabulary builder word changes. It allows you to save your changes made in Kindle Mate to your device. However when your Kindle Vocabulary Builder app is running and right in process of handling the data (eg sync with Amazon server), such an action might cause database conflicts and have a rare chance to corrupt the file.

Solutions and Recommendations:

The options to resolve the issue:

  1. Use the backup file to restore. When you Sync Changes to Kindle at the first time, Kindle Mate will create a backup file of vocab.db as vocab.db.backup in the same folder (from Kindle Mate 1.35 going forward, backup folder will be in Kindle Mate program folder). Connect your Kindle with your PC and then locate the Kindle directory manually or simply use Kindle Mate File menu-Management-Open Location: vocab.db in Kindle.  After that rename the vocab.db.backup to vocab.db. Now disconnect your Kindle safely and then quit and launch your Kindle Vocabulary Builder, it should work now.
  2. If you often sync your Kindle Vocabulary Builder with Amazon, then all your Kindle Vocabulary words data is securely stored by Amazon and up to date. You can simply delete the vocab.db in the Kindle  and Kindle will automatically recreate the database and download all your data. A restart may be required.


There are some recommended steps to avoid the issue in the most cases.

  1. Always fully sync your Kindle Vocabulary Builder with Amazon (via wifi) every time you want to batch change the data. It will securely save your data to the cloud and ensure the data consistency.
  2. Ensure to quit/terminate the Kindle Vocabulary Builder app BEFORE you want to sync changes to your words with Kindle Mate.  Instructions:  Launch the Vocabulary Builder then touch on ‘<‘ (backward icon,not Home icon) to quit.
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