“‘Raven-Installer’ is damaged and can’t be opened. You should eject the disk image.”

Description

Solution

It may be the case that the Raven installer is being blocked by Gatekeeper, a new security feature on Mac OS High Sierra. To bypass Gatekeeper, just Control Click (or Right Click) and choose Open from the menu options. A message appears warning you that the app is from an unidentified developer and asks if you are sure you want to open it? Click Open.

If that doesn’t work, or you want a more detailed explanation about why Gatekeeper is a problem, please read:

How-To Open Apps Downloaded From Anywhere, macOS