User interface freeze
Working with large movie files sometimes causes the whole computer's user interface to freeze, necessitating a hard reset.
This happens when trying to speed up large, long running video files. Load up 30 minute video clip, and run the clip job duplicate with speed change. It creates the .mlt file, and then 1 job starts running.
Pretty soon all 20GB of my RAM has disappeared and the system is swapping until completely frozen.