DISCLAIMER: this is not my post is only a copy, in case the original get deleted or whatever, posting on my personal blog get easier for me to find it. You can find the original one in this link at the end of the post. I recently found myself with a Windows guest for which I didn’t have the Administrator password or any way of getting it. Nevertheless, I needed to make configuration changes to it. As I had no need to recover the old password, I was looking for a way to simply replace the Administrator password with one of my choices.