macOS and Konftel EGO

Option 1

Please hold down the Control and Option keys when double clicking the application icon (these may be labeled as CTRL and ALT on some keyboards). Keep holding the keys down until you see the dialogue prompting to install the driver.

If that doesn't work please try the following:
Shift + Control + Option => reset all settings and request driver re-install
Shift + Control  =>  install kext if not already installed (Control is sometimes labeled "CTRL", and Option "Alt", depending on region). 

Option 2

If the "reset" does not resolve the situation, there is a way to manually check the installation manually:
  1. Open (from /Applications/Utilities)
  2. Enter the following command, including the special characters exactly:
    sudo kextutil /Library/Extensions/KonftelUpdaterSupport.kext ; echo $? 
This will prompt to enter an administrator password, then output some information followed by a single number. The output will differ depending on the host computer, but what matters is that last number. If it is zero, the driver is installed correctly and is working, if it is 27 the user has not consented to allow the driver to be used (System Preferences :: Security and Privacy), and if it is any other number then there is a problem with the software itself (the number may indicate what is wrong).