I had read about this kind of malware threat but until last week I had not yet encountered anything like it in the wild, what I found was not even real ransomware, althought named the same as a real file locking nasty the one I encountered was in fact fake and the giveaway clue was the prescence of a virtual drive (z:) to give the illusion of there being a serious problem in your files.
Simple to remove in this case but had it been the real thing it might have been another story.