When I boot up and log in to my Windows 7 PC, MM 4.0.5 automatically launches and immediately crashes, displaying a pop-up error messagebox titled with the last selected track, and saying 'Invalid Pointer Operation'. When I 'OK' this messagebox, a new error messagebox pops up with the same track details as a title, and message saying 'Access violation at address 00000000. Read of address 00000000". When I 'OK' this message, it just pops up again - and again, and again. The only way to escape the never-ending error messagebox situation is to use Task Manager to kill the MM application.
I suspect this problem is caused because when I installed 4.0.5, unknown to me (or maybe I missed the notification), it configured itself as the default Autoplay application for my iPod Touch. This means that when Windows starts up and the iPod Touch is plugged in to a USB port, the iPod is recognised as a newly connected device and the Autoplay option is triggered, launching MM. However, at this point, the Windows startup procedures are not complete - for example, the connection to the NAS drive that the MM library is set to look at, and is trying to automatically scan for changes, is not yet established... anyhow, for whatever reason, launching MM via Autoplay when Windows starts up causes this unfortunate crash. Repeatably. If I unplug the iPod before booting, it doesn't occur.
I've now reset the Windows 7 Autoplay option for my iPod, so it doesn't try to launch MM at bootup time, and so I no longer get the MM crash when the iPod is connected at bootup, and I can subsequently launch and run MM 4.0.5 without any problems.