If you use Amazon’s Send to Kindle service to transfer personal documents or eBooks to your Kindle devices or apps, encountering an internal error labeled as E999 can be both confusing and frustrating. This error often appears without clear explanation, halting your workflow and making file delivery to your Kindle impossible until resolved. In this article, we’ll delve into what the E999 error signifies, why it happens, and most importantly, how to fix it with trustworthy methods based on real-world troubleshooting insights.
TL;DR
The E999 Send to Kindle internal error typically means the document failed to process due to unsupported formats, file corruption, or temporary server issues. The error is fixable by checking document formats, renaming or converting files, reinstalling Send to Kindle software, or using an alternative delivery method. Ensuring your Amazon account is properly synced and connected to Kindle services is also critical. If all else fails, contacting Amazon customer support can help identify backend issues causing the error.
Understanding the E999 Send to Kindle Error
The E999 error code in Amazon’s Send to Kindle service is a generic internal processing failure. While Amazon doesn’t officially explain this error in detail, multiple users and developers who have worked with the platform interpret it as the system encountering an unexpected issue during file conversion or delivery.
E999 may occur when:
- The file format is not supported or unusually formatted.
- The file size exceeds Amazon’s system limits.
- Your account synchronization has failed.
- Amazon servers are experiencing temporary outages or disruptions.
- There’s a software bug in the Send to Kindle desktop app or web API.
Let’s walk through a step-by-step guide on how you can resolve the E999 error and resume smooth use of the Send to Kindle service.
1. Verify the Document Format
The most common culprit behind E999 errors is an unsupported or malformed file. Amazon only supports the following file types with Send to Kindle:
- .doc and .docx
- .mobi
- .azw and .azw3
- .txt
- .rtf
- .html and .htm
- .jpg, .jpeg, .png, .bmp, .gif
If your document is not one of the accepted formats, or has special embedded fonts, scripts, metadata, or macros — particularly in PDFs or Word documents — it may throw an internal error when the service attempts to convert or deliver it.
Solution: Try converting your document to a more Kindle-friendly format such as .mobi or .azw using software like Calibre, then retry sending it.
2. Rename the File
Some users have resolved the issue simply by renaming the file. Internal Send to Kindle processing queues occasionally get stuck due to previous failed attempts that were cached.
Action steps:
- Rename your file to something unique and simple, avoiding special characters.
- Ensure the file extension is correct and not changed during renaming.
- Reattempt sending via your preferred Send to Kindle method (email, drag-and-drop app, or browser tool).
3. Reinstall Send to Kindle Software
If you’re using the desktop application (Windows or macOS), the software itself might be experiencing internal bugs or local caching problems.
To fix:
- Uninstall the current Send to Kindle application.
- Download the latest version from the official Amazon Send to Kindle page.
- Restart your computer after installation.
- Send the file again to validate if the error persists.
4. Check Your Wi-Fi and Network Configuration
Although often overlooked, unstable or heavily filtered internet connections can disrupt the delivery of files, triggering an internal error like E999 mid-transfer. This is especially true when using corporate networks, campus networks, or VPNs that inspect or throttle certain types of file transfers.
Steps to troubleshoot:
- Switch to a different, private Wi-Fi network.
- Temporarily disable VPN and firewall to test the connection.
- Ensure there are no parental or administrative controls blocking Amazon domains.
5. Try Email-to-Kindle Instead of Desktop App
If Send to Kindle apps aren’t working reliably, you can alternatively email documents directly to your Kindle’s unique address (e.g., yourname@kindle.com), which Amazon assigns to your account.
How to use Email-to-Kindle:
- Check your Kindle email address in your Amazon account settings under “Manage Your Content and Devices.”
- Ensure your sending email address is listed as an approved sender.
- Attach the document as-is (do not drag and drop it into the email body).
- Use “Convert” in the subject line if you want Amazon to convert a PDF to native Kindle format.
6. Clean Up Metadata and File Properties
Files generated by certain software like Microsoft Word, Adobe tools, or third-party eBook creators may contain metadata that confuses Kindle’s processing systems — leading to E999 errors.
Tips:
- Open the file’s properties and remove Author, Title, and other metadata.
- Use software like Sigil (for EPUB) or Calibre to clean up file metadata.
- Export to plain text or re-save the file through a reliable PDF or DOC converter.
7. Check for Amazon Service Status Outages
Occasionally, the issue may lie not with you but with Amazon’s own servers. The Send to Kindle service is dependent on Amazon’s document conversion infrastructure, and during periods of high load or maintenance, the system may throw internal errors indiscriminately.
To check the status:
- Visit the Downdetector Amazon page for real-time error reports.
- Check Amazon’s Kindle forums and Twitter support feed for announcements.
If the system is down, you may simply need to wait a few hours and try your upload again later.
8. Contact Amazon Customer Support
If none of the above methods resolve the E999 error, it’s likely the issue is related to your specific Amazon account, Kindle configuration, or an internal user profile problem. At this point, contacting Amazon’s Kindle support is the most reliable course of action.
Have the following ready when you contact them:
- Your Amazon account email and registered Kindle device(s)
- Exact file name(s) you attempted to send
- Method used (email, desktop app, browser etc.)
- Timestamp of your last failed attempt
Amazon support can check the server logs on their end and often provide a fix or suggestion based on backend processing issues.
Prevention Tips Going Forward
To avoid encountering the E999 error again, here are some proactive steps to follow:
- Always convert documents to .mobi or .azw3 using trusted tools before sending.
- Use a consistent file-naming structure, avoiding special characters.
- Perform regular Kindle syncs and maintain software updates.
- Log out and log back into Amazon services periodically to refresh your account state.
Conclusion
The E999 internal error in Amazon’s Send to Kindle feature is a catch-all message for processing issues, but it’s not insurmountable. By understanding the causes, adjusting your workflow, and taking advantage of alternate sending methods, you’ll likely resolve it quickly and prevent it in the future. For persistent or unexplained errors, Amazon’s technical support remains your best ally in restoring normal service.
Reliable document management and a working knowledge of Kindle’s processing requirements will ensure you enjoy uninterrupted access to your documents anytime, anywhere on your Kindle device.