When a translated EPUB will not open, repeating the translation is not the most informative first step. The download may be incomplete, the reader may be using an older copy, or a particular part of the EPUB may be causing trouble. Narrow the problem before spending time or credits on another task.
Keep both the original EPUB and the downloaded result. Avoid overwriting either while diagnosing the failure.
First confirm what you downloaded
Return to the completed task and identify the actual result file. Check its extension and whether the browser reports a finished download. A partial download, an error page saved under a misleading name, and a complete EPUB are different things.
Save a fresh copy to a recognizable location if the first download was interrupted. Use a distinct filename, then import that copy into the reader. If the reader keeps showing the old version, check for duplicate titles in its library rather than assuming the new download is identical.
Open a passage you know to identify the edition. Original, translated, and bilingual books can share a cover, making it easy to test the wrong one.
Use another reader to locate the problem
Try the exact downloaded file in a second compatible EPUB reader. Also open the original in both. Keep the comparison small and specific:
| Observation | Next area to investigate |
|---|---|
| Neither source nor result opens | Source integrity, protection, or reader compatibility |
| Source opens, result fails in both readers | Download or output-file structure |
| Result works in one reader only | Reader-specific display or compatibility |
| Downloaded EPUB works, imported device copy fails | The transfer or receiving conversion stage |
This does not identify every cause, but it prevents unrelated fixes. Do not change a filename extension to force a reader to accept the file. The extension does not repair the underlying contents.
For deeper structural checking, use the EPUB validation guide. A checker can report package problems; it does not establish that the translation's meaning is correct.
Inspect chapters, images, and fonts separately
If the file opens but looks wrong, record the smallest reproducible location. “The whole book is broken” is difficult to investigate. “Chapter 7 opens to the end of chapter 6” points to navigation or reading order.
For chapter problems, compare the visible heading, contents entry, and surrounding paragraphs. Check whether the source already has the same issue. A printed contents page and the reader's navigation menu are not necessarily the same thing.
For images, inspect the same illustration in the source and result. Note whether it is missing entirely, clipped, or simply rendered at a different size. Check the caption and nearby paragraph too. Image retention does not imply that embedded lettering was translated.
For fonts, enlarge the text and try another reader font where supported. Replacement boxes or missing accents can come from a font that lacks characters. If the characters are wrong when copied as text as well, investigate the content rather than the font alone.
Check whether bilingual length explains the display
PDF Craft's bilingual output places each translation after its original passage. A long source paragraph may therefore occupy several screens before its translation appears. That can feel like missing text even when the order is correct.
Compare a short passage and a long one. If uninterrupted reading matters more than local comparison, a translation-only edition may fit better. Do not assume bilingual means synchronized columns or identical page counts.
Similarly, reflowable EPUB pagination changes with font size and screen dimensions. Compare chapters and distinctive phrases, not page totals, when checking completeness.
Preserve a useful problem sample
Keep the task identifier, the downloaded filename, the reader and version, and the exact chapter or phrase. Record whether the original works and whether a second reader reproduces the issue. A screenshot can help show clipping, but include enough text to locate the passage without relying only on page numbers.
When contacting support, do not automatically attach an entire private book. Start with the necessary task details and an approved example. The privacy checklist covers that boundary.
If another processing attempt is appropriate, review the source and settings first. Translation is charged by usage; current rules are on Pricing. The before-upload checklist can help resolve source problems before another submission.
Once the EPUB works in a desktop reader, move to your device using its supported import route. For Kobo, follow the Kobo guide. Keeping download, file structure, reader display, and device import separate makes failures much easier to understand.