My adice would be to take note of #3, 4, 5 and 6....they are all reflective of what can happen.
The SH3 engine is now over five year old and loads ALL of the SH3 world files and campaign layers, unlike the newer SHIV enfine for example which only loads six months at a time.
No doubt one of the above responses will have been the reason, please advise us of which one so the rest of the community can share in the knowledge
