NOTE: This issue is now corrected by Universal Control-AI 220.127.116.11286
There is currently a known issue with Universal Control AI 18.104.22.168882 on Mac OSX 10.10 where the StudioLive AI mixers do not show up in Audio MIDI Setup as an audio device, which prevents recording with AI consoles on 10.10 Yosemite.
It is suggested that you complete a Manual Uninstall of Universal Control AI on your system before installing Universal Control AI 22.214.171.12418. Instructions can be found here:
The problem is related to the Firewire driver version included in UC-AI v28882. Until a proper fix can be released, users can install an older version of UC-AI as a temporary workaround. Universal Control AI 126.96.36.19918 includes a slightly older version of the Firewire driver component, and it is functioning correctly on 10.10 Yosemite. Universal Control AI 188.8.131.5218 for Mac can be found on the StudioLive AI product page Downloads section, under Legacy Software Downloads.
**NOTE: This workaround will correct the issue for single StudioLive AI consoles being used with Mac OSX 10.10 Yosemite. For cascaded StudioLive AI consoles, UC-AI v24818 will allow control of the mixers, but recording with cascaded mixers on an Mac OSX platform requires the newer Firewire driver in UC-AI v28882. This means that the workaround of installing UC-AI v24818 for 10.10 Yosemite support does not apply to cascaded mixers, and recording cascaded mixers on 10.10 Yosemite is not possible at this time. A full resolution should be forthcoming.
For up to date information on the latest compatibility issues with Yosemite please check this link