VC 13 starts D 13 then shuts down

This is an intermittent problem, but it is just happened twice in a row.

Normally when I double-click VoiceComputer it starts Dragon and then opens the main menu. However, the last two times I started it in opens Dragon and then shuts down. If I then say VoiceComputer it will reopen and work normally.

I'm using the latest downloads of both VC and Dragon on Windows 8.1.