I was converting an eBook or an .indd files to EPUB version and unfortunately I got this warning “Malformed byte sequence: Invalid byte 1 of 1-byte UTF-8 sequence.” So I dig on Mobile and eBook forum to know what this error main and how to rid of this warning and so sad I didn’t found any luck, so I began working it myself and yep I found the answer and I want to share this to you.
There are only few steps to get rid this warning, I’m using Notepad++ a free text editor; you can download this on the net.
Open the file in Notepad++ that causing the warning.
Under Enconding Tab select Convert to UTF-8 and save the file and you’re done.
Hope this will help in your ePub conversion.