Originally Posted by wannabee
Spent the day finalising a book. (I hope) must have unzipped, edited and rezipped 30 times. Used 3 press and flightcrew every time to validate with no errors.
No scripts, just right click "extract all" and right click "send to zip file"
If you're lucky, that might work. It would require the zip to have zipped the mimetype file first, and to not apply any compression to it. I'd advice checking with epubcheck as well, which I know checks that the mimetype file has been done correctly.