我试过一个简单的测试你说的问题。但我无法重现这个问题。

I tried a simple test for the issue you said. But I could not reproduce the problem.

 我在我的设备中安装了更新，并尝试在本地计算机和模拟器中使用MediaPlayer。  MediaPlayer可以在本地计算机和模拟器中正常运行。并且RandomAccessStreamReference.CreateFromUri（）
方法也没有给出异常。

 I installed the update in my device and try to use MediaPlayer in both local machine and simulator.  And the MediaPlayer could work correctly in both  local machine and simulator. And also RandomAccessStreamReference.CreateFromUri() method does not give an exception.

我有一些问题。这是否发生在另一台机器上？你有关于此的测试吗？ 你如何称MediaPlayer播放媒体？你能告诉我一些可以重现这个问题的代码片吗？

I have some questions. Does this happens on another machine? Have you test about this?  How you call the MediaPlayer to play media? Could you show me about the code snippet that could reproduce the issue?

祝你好运，

Roy