The workaround from the OP does not work for me.
Not being able to complete either The Esseles or The Black Talon is excruciatingly frustrating.
Get your DEV team to do something useful and fix these bugs! Instead of bringing out more new stuff, fix the old stuff first.
It still works for me. You must be doing something wrong. As long as you don't see the hyperspace animation on screen it won't crash. You have to alt+tab(fullscreen) or minimize(windowed) immediately after talking to Harken, before the animation. You also need to wait long enough for it to finish. I just ran Esseles again and it still works.