HUGE lag, then nothing happens

I downloaded the beta and on the first day, it worked fine. But the next time I opened the program and tried to open any of my scrivx files, it hangs on the Project Templates window, says Not Responding, and then sits there, whited out and unworking.

I then tried to open some of the un-updated scrivx files with my old version (1.9) and they also hang, at the same point.

I can’t get anything done and I don’t know how to fix this.