An issue was discovered with the latest update of Universal Control-AI for the AI console mixers where Universal Control-AI will not see the 16.4.2AI console over the network.
The problem only exists when using Universal Control-AI v1.6.0.30286, it only affects the 16.4.2AI console, and only over a network connection. All other AI mixers are correctly seen on the network, and the 16.4.2AI is still seen by Universal Control-AI via a firewire connection.
Software Engineering is currently working on a fix to be released in a future update, but until then the workaround is to either use Firewire or iOS devices for control, or to install the previous version of Universal Control-AI for your OS.
There were no bug fixes in 1.6.0.30286, so using a previous version should not pose a problem in that regard. The only change or update in 1.6.0.30286 was to allow VSL-AI to grey out the features that are disabled on the mixer when it's set to an HD sample rate mode.
http://www.presonus.com/products/StudioLive-AI-Series/downloads
On Windows PC's, the previous version you would use is Universal Control-AI v1.0.2.24818. Full uninstall instructions for Windows can be found here:
On Mac OSX, there are two previous versions, so which one you should use will depend on your OSX version and your mixer usage/configuration. Full uninstall instructions for Mac can be found here:
On OSX 10.8 and 10.9, the version to use would be Universal Control-AI v1.0.2.28882. This version has the updated 4.1.4 firewire driver needed to support recording with cascaded StudioLive AI consoles.
On 10.10 Yosemite, because of the incompatibility of the 4.1.4 firewire driver with OSX's new kernel extension security policy, the version to use would be the prior 1.0.2.24818. This version does not support recording cascaded AI consoles on Mac OSX though. In order to use cascaded StudioLive AI consoles on 10.10 Yosemite, see here for a workaround