screenshots storage place back to desktop impossible
The problem is that the command:

defaults write com.apple.screencapture location /Desktop/


will set the default location for screenshots to be /Desktop/. What you actually want is to set it to be /Users/yourusername/Desktop/.

Try this, replacing yourusername with the username for your account:

defaults write com.apple.screencapture location /Users/yourusername/Desktop/