Crash on changing dynamics font size/failure to restore session

I was working on a score just now and wanted to change the size of the font for dynamics (because the default size 12 is way too big--it should be 8 or less). I right clicked, changed the size to 8, and exited to find that the dynamic had disappeared. So I hit undo, and the program crashed. It didn't happen with the mezzo-forte dynamic, only piano.

I started the program up again and it said that it had closed unexpectedly, asking if I wanted to restore the session. I hit yes, but instead of my score, the demo score came up.

I tested again for the bug to see if it was a one time thing, but it crashed again. Now the program won't start, task manager won't open, and my system is apparently frozen.