Also, future MyDefrag runs will fail silently without explaining the problem to the user (unless they go read the log file).
This alone is a big problem IMO... it makes absolutely no sense as to why MyDefrag won't start until I look at the log file and find that the MyDefrag process I just closed was still running in the background.
Two things really need to be fixed in regards to the way that's handled: 1) a window really should pop up any time MyDefrag closes without user interaction or the script completing, saying something to the effect of "I closed because...". That may even help figure out why MyDefrag crashes after analysis of some drives. And 2) when MyDefrag is closed while processing, it should pop up a "Please wait while MyDefrag shuts down..." window so people know it's actually still running but just processing the last file.
IDK if that's going to be something added during beta, but I really think it should be, it's just weird behavior as it is now. But that's what forums are for, right?