I have noticed that when editing my videos in Movie Maker 2012, .wmv files lag and freeze the program while .mp4 videos are fine! Why would your own video format play worse in your own program than a third-party format? I do not have file preparation on and I do not wish to turn it on since it decreases video quality, but the videos are only in 720p and not 1080p format so they should play just fine (my computer has 16gb of ram and 4gb of video ram). Is there a way to fix this without converting the video to mp4? Because converting it always lowers the quality of the video by another level. I'm using Windows 10 with the latest update, plus my codecs and drivers are all up to date as well. Thanks in advance.