How can I run Warcraft 3 on my new MacBook Pro I recently bought the digital copies of Warcraft III: Reign of Chaos and Warcraft III: The Frozen Throne from the blizzard store. They are registered with my blizzard account but when I download the zip file it opens a downloader but my computer says it can't be opened because it is from an unidentified developer. What can I do about this? 

The error is shown in this image
From https://us.battle.net/support/en/article/playing-older-blizzard-titles-on-mac-os-x-10-7-lion : 


  Warcraft III will only run on Mac OS X 10.7 if your operating system
  was upgraded from 10.6.X and only if the Warcraft III installation was
  patched before the operating system was upgraded. There is currently
  no way to install or patch the game on Lion.


So you need a 10.6 system to bootstrap from.