Just done a clean install of the iso posted on http://www.wincert.net/forum/topic/8906-official-windows-7-sp1-disks/. It's professional version x64 - all works fine in virtualbox version 4.2.12 r84980 (it's the very latest version as of yesterday) along with the latest VirtualBox 4.2.12 Oracle VM VirtualBox Extension Pack. I've just completed another "component strip" and that is now working. There's a few features I chose to leave enabled between this and the previously failed version. The exact steps taken in win toolkit is: 1) main tab > advanced > component remover > browse > browse to the ISO location downloaded from the link above. Once this is imported there's a few choices of win7 version. Mine is professional x64. 2) I selected that version, it's mounted and i remove the following features. Attached are the screenshots of the exact configuration that is working. I didnt' think i'd be able to replicate the error however there's only a few extra components that I removed which caused errors so might well be able to. Every installation so far though, despite getting it working has a dialog box popping up on first login to the desktop displaying the following error: "The program can't start because WMDRMSDK.dll is missing. Try re-installing". Clicking ok lets the user into the desktop This is a much more important error to have fixed as I believe the other can be narrowed down quite quickly. Edit: Should also mention that the checked options are the options i'm removing.