Among the various things that I needed to do on Saturday, I got to looking at why VirtualBox Windows guests could not shut down and the processes killed. Though it wasn’t clear at the outset, my suspicions began to centre on the sound hardware emulation and how it interacted with the host’s sound capabilities. A look at the VirtualBox log sent me that way after a spot of experimentation with reinstalling Windows 7 and adding the Guest Additions along with removal and reinstatement of the same for a Windows XP guest that makes my like easier. It also seems that the same problem blighted the start up of Linux guests too. Either removing virtual sound hardware or using the null sound driver seems to allow things to run smoothly. That may not sound ideal but it doesn’t bother me with the host providing all that I need. Also, it’s a moot point as to whether I have come across a bug in VirtualBox or whether using Ubuntu on a hardware configuration on which it wasn’t originally installed is the cause but I have found a way forward that suits me. Saying that, if I find that the issue disappears in a future, that would be even better.