Colasoft MAC Scanner 

Colasoft MAC Scanner is a utility created for network administrators who wish to easily identify the devices that are being connected to their local subnet. By using this program, they can see which computers are connected to the local subnet without their permission.

The application comes with a user-friendly interface, immediately scans the selected subnet, and provides you with detailed information regarding the connected devices. You can add the entries you wish to monitor or save for later in a database and edit their correspondent info if necessary (enter user name, workgroup name, location, etc.).

Colasoft MAC Scanner also enables you to export the fetched information to your local directories. However, you cannot choose which type of details should be exported (hostname, workgroup, IP address, etc.).

The program also displays an error message whenever I try to check if there are any updates available. Another thing that bothers me is that it's quite expensive.

In conclusion, I'd say you should try a different Windows program for identifying the devices that are being connected to your local subnet.