I encountered an issue when trying to upload EPUBs to Readwise Reader that I had downloaded from Apple Books. Turns out, it's a known issue that Apple Books exports EPUBs as folders, not files, making imports to other services problematic. To address this, I found a GitHub project that can help. Here's how to use it.
Source code (if macOS doesn't auto-extract)
3. In a terminal, grant
pack-epub write access:
chmod +x /path/to/pack-epub
4. In a terminal, convert your Apple Books EPUB
5. On the first run, macOS may block the app as it's unverified. Click 'Cancel'.
6. Go to System Settings > Privacy & Security, find "pack-epub was blocked..." and click "Allow Anyway".
7. Run the conversion again in a terminal
8. The fixed EPUB will be in the folder
pack-epub-1.0 that was unpacked by