Hi Hamish,

> Can you elaborate on how the installation files might have been modified by
> my AV? i.e. What is the typical evidence of the AV interfering?

It's just a guess on one possible problem source - Anti-Virus programs have a tendency to hook into the system at a low level and that type of intrusion can sometimes have side effects.

If you are running any anti-virus or anti-spyware programs, you might try temporarily disabling them, and then doing a fresh installation of MoI and see if that behaves any differently.

- Michael