Last week I experienced a weird problem on my Mac running Mountain Lion. Every time I tried to delete something, Finder asked me for the root password. The error displayed: “Finder wants to make changes”.
So I tried to restore the permissions on my disk, but that didn’t help. The problem was that the .Trash folder in my own home folder was no longer owned by my account, root was the owner (for some reason). To fix this, simply copy and paste the following line into a Terminal.app window:
sudo chown $USER ~/.Trash
This will change the owner of the .Trash folder to your account. You have to do this from the Terminal since this folder is hidden from the Finder.