Hmm, my Photos folder has suddenly required admin permissions to write to it, and I'm not sure why. It may explain why Lightroom has stopped running unless I'm an administrator, but I can't remember doing anything to make it do that. On looking in the security tab of the folder, I have a couple of weird things. There's the usual SYSTEM group, along with HomeUsers and Administrators (and Users and AuthenticatedUsers on my Documents folder I compared it with.) Both also have a couple of accounts that I have no idea about, though. One is "Account Unknown" with a string of letters and numbers after it, and one is "uuid: *load of numbers*[edit: I believe this is created by adding a Media Centre Extender) What are these for? How can I see where they are coming from, what group they're in, etc. I think my user settings may be messed up as I carried the folders over from my Vista install. Another thing, when looking at my User Profile settings, it shows that my profile is 9.23gb! I don't mind it taking that much space, but what is it using it for?