I had a discussion about this issue and similar to http://forums.cnet.com/5208-6617_102-0.html?forumID=11&threadID=256421&messageID=2540073 they found it was fixed if they shrank the partition by 1GB and then grew it back up 1GB.

There must be a bug in that partition software or maybe on Microsoft's end but I can't find the bug or decide which end of the stick to blame.

Bob

PS. I would be remiss if I didn't write the word "Backup" before trying that.