Export/Import P6 to MS Project (MPP) - MPP not an option

In both our last V7 and current V18 versions, while MPP is initially an option to import/export, it is now not in the list to select.  While on V7 i uninstalled both P6 and MS Project and reinstalled and the option appeared, but now it's gone.  I've tried this a few times with the same situation.  I understand my company runs updates in the background frequently which is what is affecting this being available.  Anyone have a workaround by chance other than having to use a seperate completely network-disconnected machine?