We have several PC in our house, all running Windows 10 and Movie Maker has begun to fail in various ways on all of them as of Wednesday 11/23/16.

One will not allow .mp4 files to be dropped into the working area. Another looks like it is running, allows edits but when the movie is saved in mp4 format, it will not play correctly. Large parts are black and frames are skipping and freezing.

Other PC's all failing in similar ways after no changes from me.