Apple - Allow button not working in system preferences

This worked for me on High Sierra 10.13.4:

• System Preferences > Keyboard > Shortcuts > Select 'All Controls'

Then:

• System Preferences > Privacy & Security > Press 'Tab' until 'Allow' is selected > Press 'Spacebar'

*Note: the Privacy & Security page may need to be unlocked before 'Tab' will work.

*Note: After open Security & Privacy and selecting General tab you should push tab key to select allow button after that push space bar key!

Hope this helps!

Credit to @dansanduleac's answer on GitHub

If you are connecting to the computer remotely with software such as TeamViewer, VNC etc. it will not work, because macOS doesn’t allow you to press “Allow” button through other applications. You have to directly press that button with your trackpad.

We can use Apple Script to click on the Allow button as follows:

1. Press Shift Command 4 to start screen capture (but don't actually go thru with this):
2. Hover over the Allow button and note the coordinates (e.g. 620, 534)

3. Open a Terminal window and use those coordinates in a script:

   osascript -e 'tell application "System Events" to click at {620, 534}'