UPnP, or Universal Plug and Play, is a type of residential network connection that allows computers to share files and folders directly with other computers or devices. Your MacBook features a UPnP file sharing service that enables other Macs to access the files on your hard drive. Use the "System Preferences" feature on your Mac to control the file sharing settings of your computer.
Click "System Preferences" from the Apple menu at the top of the screen.
Click the "Sharing" icon under the "Internet & Sharing" section.
Click the "File Sharing" check box in the window that appears. Type your administrator password into the prompt and click "OK."
Click the "+" button under the "Shared Folders" option to select which folders you want to share with other users.
Click "OK" to enable the UPnP sharing on your MacBook.