Hi Phil,
It's hard to tell from your description of your problem whether you are having troubles with video content you personally created or video content that was commercially created that uses DRM; for example DVD movies that you purchase from a retail store or online via one of the big content streamers such as Netflix or Amazon. You should know that for nearly 2 years now (July 29, 2015) W10 removed all capabilities of playing commercial DVD movie content from their OS, and that's why you cannot play commercial Music or DVD content on your DVD player unless you buy the Microsoft Media Player from their App Store for $14.99. Folks often try VLC or other free or low-cost media players in the Apps Store to correct this problem (solutions at $14.99 or less). I went through this last year and have multiple posts here about it. Neither VLC player or any of the other players in the Apps Store will play the 5 or 6 movies I wanted play on my W10 laptop for a movie event we had in my Park here last summer. I even spent the $14.99 to buy the Microsoft player thinking that would fix the problem but it didn't. According to one of our frequent contributors (brkkab), he had this same problem with many of the DVD movies in his library and finally solved it by purchasing the
Powerlink DVD Creator suite for $79.99 online. I am planning on getting that for my laptop as well, just haven't done it yet, so I haven't personally verified it works on the movies I was trying to play on the DVD player on my W10 laptop. Just passing that info along to you.
Don't know how you were playing your Movies before over your network in W10, but you simply may have accessed a movie that you thought you were playing prior to the W10 CU update coming in back on Apr. 11th, but may have indeed been some other movie. Again, the real issue is if you were playing a movie on a W10 version earlier than the current
v1703 (CU), chances are it wasn't a commercially purchased movie, but rather one you made with movie creation software such as Movie Maker which you mentioned or iLife for Windows or similar. I can tell you for a fact that VLC won't play just about any of my commercially mad movies either before this months W10 update or after.
Let us know what kind of content you are attempting to play. Nevertheless, I suspect you are going to have to cough up the $80 if you intend to watch purchased movies streaming on your network whether sourced from a DVD player or a Media Storage Station or NAS device etc.
Best,
<<<BIGBEARJEDI>>>