First off, the good news! SpaceX is now confident enough in their procedural fixes for Falcon 9 that they have announced their next launch date:
December 16early January, from Vandenberg AFB. Payload would be a set of ten next-generation Iridium satellites. [Edited per SpaceX news release 12/7. Original date was reported on SpaceflightNow, but I’m not sure where they got it, since it doesn’t appear anywhere on SpaceX’s website.]
Second, Roscosmos has convened a failure investigation board and begun combing through the data from the failure of Soyuz-U with Progress MS-04. This was to have been the next-to-last flight of the Soyuz-U. Everything appears to have been nominal through the first and second stages of flight, but during the third stage, something went badly wrong. One account has a premature engine shutdown command issued due to a deviation from flight path so severe the third stage’s gyro stabilization system stalled, and then Progress breaking away due to the strain. Another account has the flight proceeding normally until for some unexplained reason the spacecraft separated. It will take time to sift through the data and come to an answer; at present in Russian media, it seems the respective manufacturers of the rocket and the spacecraft are attempting to point fingers at one another.
Meanwhile, the impact region has been located. Russian authorities are combing the Tuva region for debris, and one piece appears to have been found by residents of Tos-Tevek, possibly a propellant tank (as Progress carries not just its own propellant but also supplies for ISS propulsion system).