Yaya, keychain finally quit it's infinite loop of authentication for me and allowed me to properly disable it then re-enable and reset without involving another device to activate it. One problem solved, another problem created... now my USB McIntosh D100 DAC has a 1 second audio blackout every 15 seconds no matter from what media player, youtube, iTunes, or JRiver. They must have changed something significant about USB stack and the asynchronous timing priorities. As an audiophile this is too much of a price to pay for getting keychain to finally work... hope they fix this soon because I would hate to be stuck as the only person experiencing USB audio problems and to never get a fix for it.