If you are unable to open the EPUB files, it could be because your browser does not support the format. In the current scenario, only Microsoft Edge offers EPUB support, however, you must enable the feature from its Properties. For Chrome and other browsers, you would need an extension to read EPUB files. To open an EPUB reader on Windows, you would need a dedicated EPUB reader for your desktop. Alternatively, you can convert EPUB to PDF with free converter tools to continue reading the eBook.