‘Obfuscated resource must be a Font Core Media Type’ Error from InDesign ePub publishing on Ingram Spark

When publishing an e-book on IngramSpark, it’s not uncommon to encounter errors, such as the “Obfuscated resource must be a Font Core Media Type” error. This error typically occurs when attempting to upload a font file that is not supported by the platform. Fortunately, there are several steps you can take to fix this error and successfully publish your e-book.

The first step in fixing this error is to ensure that the font file you are attempting to upload is in a supported format. IngramSpark supports the following font file formats: TrueType (.ttf), OpenType (.otf), and Web Open Font Format (.woff). If your font file is in a different format, you will need to convert it to one of these supported formats before uploading it to IngramSpark.

I was using a ttf font in my document and that was causing the error, but I used Convertio to convert the ttf to an otf file, installed that font, changed the font in InDesign to the new otf font, re-exported the ePub and it passed the inspection without error! Whew!

Another common cause of the “Obfuscated resource must be a Font Core Media Type” error is the presence of additional files or metadata in the font file. IngramSpark only supports font files that contain the necessary font data and do not have any extraneous files or metadata. To fix this error, you will need to remove any additional files or metadata from the font file using a font editing software.

If you have tried these steps and are still encountering the “Obfuscated resource must be a Font Core Media Type” error, you may need to re-embed the font in your e-book. This can be done using an e-book editing software, such as Sigil or Calibre. To re-embed the font, you will need to extract the font file from your e-book, convert it to a supported format if necessary, and then re-embed it into the e-book using your e-book editing software.

In conclusion, encountering errors like the “Obfuscated resource must be a Font Core Media Type” error when publishing an e-book on IngramSpark can be frustrating, but with a few simple steps, you can easily fix the error and successfully publish your e-book. By ensuring that your font files are in a supported format, removing any additional files or metadata, and re-embedding the font in your e-book, you can avoid this error and ensure that your e-book is published without any issues.