Hi Paul
I am running HW on Windows 10 and have recently noticed a similar problem but only with organs that use a lot of memory.
I put it down to Windows expecting programs to unload in less than a second or so and when a program, like HW, takes longer Windows thinks the program has crashed and says it is not responding.
One cure is to use the task manager to force closure, but I have found that it does eventually close after a while without doing anything.
csw900