If you are borrowing an epub, here is the procedure i use. Borrow the book and open with adobe digital editions. It will be in your document folder under my digital editions folder. Copy book to somewhere else, say desktop. Run it through Calibre. Then in the calibre folder you will find book in original and modified. Copy or move to where you store books. It has always worked for me. Maybe more steps than necessary but works for me. I then return book so someone else can borrow.
I have not been able to convert Daisy yet. Any suggestions?