so far this has happened on only two presets. the Resonator preset Beecuz and… uh, I didn't make note of the other preset 
oops. When I come across it again I'll edit this. otherwise, my midi connection has worked flawlessly.
Well, that communication error means that H9 Control has sent a message to your H9. It's expecting the H9 to reply and say it got the message, but the H9 hasn't replied. What are you doing when you see this error? Changing parameters? Saving the preset to the H9?
other child windows, such as the ones that appear when using the Eventide Store will sometimes crash the whole program. I noticed something funny I've never seen in any other windows program, the child windows ClassName ends in a seemingly random 10 digit hex number on every instance. so in moving windows the title has to be matched and not the class name (which I've found to be less reliable) phew…. ok that's it 🙂
If I remember correctly, you're working on Windows. What version of Windows are you working on? Is it just the store child window that's crashing? Or any other windows… I wasn't 100% from your description if you wanted to direct our attention to the fact that some child windows are causing crashes on your system or the difficult you've been having to have them moved to the right display in your multi-monitor setup.
