- Download The Unarchiver. The default archive utility cannot open the downloaded zip file properly, and only this alternate utility can open it properly. (Let me know if you find another one!)
- Make sure you have the zipped save file you want to open with you on your Mac.
- Right-click the file instead of double-clicking it. Unzip the file with The Unarchiver.
- Now, once you have your save folder, navigate to: User/Library/Application Support/minecraft/saves.
- Drag in the downloaded save folder into the Application Support saves.