Problem:
The installation of Indeed AirKey Runtime is completed prematurely.

Cause: 
The reason may be the outdated version of the User-Mode Driver Framework (UMDF). When installing a component, Windows tries to download a new version, but cannot do it (Windows Update service is disabled or there is no connection to the Internet) and the installation ends with an error.

Solution:
Try installing the User-Mode Driver Framework version 1.11 or later manually and then reinstalling the AirKey Runtime.
Download UMDF from Microsoft Download Center.