Yosemite causing MacBook Air 2013 to crash when connected to Thunderbolt display


My setup is a fairly standard one: 13″ 2013 MacBook Air, which is occasionally, although more often than not, plugged in to a 27″ Thunderbolt Display. I “upgraded” to Yosemite last night. Booted my machine, everything seemed fine. I was downstairs at the time, no Thunderbolt display connected. This morning, plug in to the TB display, and disaster… Blacked out...