5.0.0 does not save

The save function does not work properly. This has happened twice and is very painful. Whether you click the save icon or go through the File menu or via the shortcut keys, it doesn't work. It works for a while, and then, for whatever reason, it will not save any more. There is nothing to indicate that it did actually save, and equally, there isn't indication that it didn't save.

I'm using a 64 bit Windows 7 machine.

I don't see anything in the SoapUI vs Pro product comparison that mentions a limited ability to save.