As every fule kno, once data is on your computer, it is surprisingly hard to ensure that it has been removed. Even if you ask your computer to delete your data, or tick boxes provided by Microsoft that reassuringly suggest that details of your browsing habits might be removed, the data is unlikely to have gone far.
Now someone is suing them over it. As so often, it’s not someone with whom one has any sympathy at all. And no prizes, either for guessing what it was he wanted to keep hidden.