If a remote user is using the Send or Exchange service to transfer files to your computer that you don't need, or that you don't have room for, you can cancel the file transfer.
To cancel a file transfer to your computer
From the Connections menu, choose the remote user's name under Disconnect All Users.
The remote user is disconnected immediately and the file transfer is stopped. The file that was in the process of being transferred is not copied, but all previously transferred files remain on your computer.
If you want to restrict other users' ability to transfer files to your computer, you can change user access privileges in the Security dialog box.