Vista Media Center, USB Drives and Thumbnails

While trying to setup a new system with Windows Vista to use as my media center I ran into a strange problem. It would create thumbnails and show the video length for all videos, unless they were on the my USB drive.
But I found a way around it here Vista Media Center and Videos on Network Drives and its seems to work OK. I’d be happier with a fix rather than a work around, but sometimes you have to take what you can get.
If you’re having trouble removing folders from the “watched folders” list have a look at this post.