Depending on your Mac’s security settings, you may receive the following message when opening your PDF eBooks:
“eBook Title” can’t be opened because it is from an unidentified developer. Your security preferences allow installation of only apps from the Mac App Store and identified developers.
Follow these instructions to allow your Mac to open the eBook:
- Click OK to close the error message.
- Open System Preferences from the Dock and select Security & Privacy.
- Navigate to the General tab and click Open Anyway near the bottom.
- Select Open.