當要安裝從網路下載的 APP 時，MacOS 會回你一句 "xxx" can't be opened because it is from an unidentified developer. 這個是因為 Gatekeeper 在搞怪，只要把權限打開即可。

• 打開 System Preferences
• 點選 Security & Privacy
• 點擊左下角的鑰匙頭，旁邊寫著 Click the lock to prevent further changes.
• 打勾 Anywhere 即可