I have a big digital signage application that uses mediaelement to run the videos.
For some time now I see that when I close the application the process continues to run in the background and refuses to die ! even when I go to the process list and try to kill it.
After a long investigation I found that it is the mediaelement that is causing this problem (I created a small project that reads a local address of a movie and plays it), and the problem occurred.
It is important to mention that it doesn't occur in every OS just random ones (i.e Win 7 enterprise).
I think that it has something to do with the local file (I think maybe the mediaelement is still "holding" the file in a buffer after the application closes).