This indeed is a big issue. MS does not seem to have any solution for this. I started getting this problem post 25-Nov or so after some updates on my Surface 3. The FB app is just not opening up and keeps on crashing. There are many active threads on this on MS forums, but none seems to have a solution. This is indeed disappointing that an app as important as FB is not working on Windows 10 for desktop and tablets. Also, Windows Central does not even seem to be aware of this issue. I wonder how?