I've just downloaded see music to try it. I've watched some tutorials, made a midi and video mp4 file and just started editing the scale and what not of the video when it crashed. The program now crashes every time I have it open for a couple of minutes. It also crashes when I run it in the background and I am using my daw, or chrome. Just suddenly, without any reason or warning. I tried about a dozen times and it keeps crashing. How can I use this program like this?
I made a screenshot of what it shows when it crashes:

Sorry! Yes, there was an issue in Unity, the framework the app is built on, that caused this issue on Windows.
The crash should be completely fixed in Version 5.4 - you can download from seemusicpiano.com