Dragon accidentally banned the entire Internet for a few hours.
Chance: I limped through an eight-hour session getting the basic tracks done on some fairly complex songs. The musicians were just slightly over their heads, IMO, and the process had been progressing slowly, but with satisfactory results. As I stood up for the last time, I bumped the table (I only work on-location, this was a rehearsal space) and it jiggled my computer enough to momentarilly interrupt power. I had not manually saved anything that day. Goodbye session!