Some Microsoft Word docx files uploaded to AEM Assets have thumbnails that are blurry and illegible.
AEM Assets does not generate docx thumbnails, instead it extracts them directly from the docx file archive. If Microsoft Word happens to generate a faulty or blurry thumbnail, the same is carried over to AEM.
As a workaround, a command line tool could be employed to generate thumbnails. For example:
The tool could be applied via the Command Line workflow process step and the configuration for this would be similar to Image Magick.