To disable (turn off) Mac OS X 10.5 (Leopard) file sharing, follow these steps:

1. From the Apple menu, click System Preferences.
2. In the System Preferences window, click the Sharing icon in the third row. This icon is circled in white in the graphic below:

   

You will see the Sharing window, which looks similar to the one below:

3. Confirm that the checkbox in front of File Sharing in the left-hand column does not have a check mark in it. If it does, click to remove it. Removing a check mark will disable file sharing on your computer, which will make your computer more secure.