Unfortunately, on macOS, when double-clicking on an epub renamed to .zip to automatically open it will just try to compress it again as it appears the mimetype file of the epub is confusing it.

It looks at the first entry (the mimetype) and sees it is uncompressed and so thinks the entire file is uncompressed and so "smartly" tries to compress instead of uncompress. Stupid really as you can add uncompressed files to any zip and they might come first.


Either the command line tool unzip or pdurrants applet will work.

I have attached a very very simple test case with a cover png file. I created this as an epub3 in Sigil. On my macOS Desktop the cover image does show up. It passes epubcheck.

Please use it for your testing.

See attached test_books.epub

lol - something Windows does better than Mac....that doesn't happen often!

It happens a lot more then you think. Apple doesn't care what they break when they release a new OS version. Microsoft wants to try to keep compatibility. Apple doing away with 32-bit software was done for no good reason. Some of the underlying settings choices Apple makes for their defaults are really stupid. Worse then most of Microsoft's default settings.

JSWolf, This is not the place for debating macOS vs Windows or to express unrelated opinions. Please stick to the thread topic which it to help the original thread poster, if you are going to post.

Two out of 3 of your posts in this thread are unrelated to helping.