Why are computers missing from the network map?

The network map is a graphical view of the computers and devices on your network that shows how they're connected. Sometimes, Windows can't detect all of the computers and devices on a network, or can't place all of the computers and devices in the right location on the map. Here are some reasons why problems can occur with the network map problems and some solutions to try.

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A computer or device doesn't appear on the network map

This can occur for the following reasons:

  • The computer is running Windows 7 or Windows Vista and is connected to a network with the Public network location. Windows can't detect a computer on a Public network. To fix this problem, you can try changing the network location to Home or Work or try connecting to a network that already has a Home or Work network location. For more information about network locations, see Choosing a network location.

    Warning

    • When you connect to a Home or Work network, your computer becomes visible to other computers around you, which increases your risk of being exposed to malicious software from the Internet. You should connect to Home or Work networks in places where you know and trust the people and devices on the network, such as your home or workplace. Avoid assigning the Home or Work network location to networks in public places, such as coffee shops, hotels, or airports.

  • The computer is running Windows 7 or Windows Vista and the Link Layer Topology Discovery (LLTD) protocol is disabled on the network adapter. Windows uses the LLTD protocol to map computers and devices on a network. To enable LLTD, follow these steps:

    1. Open Network Connections by clicking the Start button Picture of the Start button, and then clicking Control Panel. In the search box, type adapter, and then, under Network and Sharing Center, click View network connections.

    2. Right-click the network connection, and then click Properties.

    3. Select the Link-Layer Topology Discovery Mapper I/O Driver and Link-Layer Topology Discovery Responder check boxes, and then click OK.

  • The computer is running Windows 7 or Windows Vista and network discovery is turned off. To turn on network discovery, follow these steps:

    1. Open Advanced sharing settings by clicking the Start button Picture of the Start button, and then clicking Control Panel. In the search box, type network, click Network and Sharing Center, and then, in the left pane, click Change advanced sharing settings.

    2. Click the chevron Picture of the chevron icon to expand the Home or Work network profile.
    3. Click Turn on network discovery, and then click Save changes. Administrator permission required If you're prompted for an administrator password or confirmation, type the password or provide confirmation.

    For more information about network discovery, see What is network discovery?

  • The computer is running Windows XP and the LLTD protocol is not installed. Before a computer running Windows XP can be detected and appear on the network map, you need to install the LLTD protocol on that computer. For more information, go to Network Map in Windows Vista Does Not Display Computers Running Windows XP on the Microsoft website.

  • The computer is running Windows XP and firewall settings are preventing Windows from detecting it. Check the firewall settings and make sure that file and printer sharing are enabled. If you are using Windows Firewall, see Understanding Windows Firewall settings. If you are using another firewall, check the information that came with your firewall.

  • The device doesn't support the required protocols for Windows 7. Check the information that came with the device to see if it has a Windows 7 logo. If the device has the logo, it should appear on the network map. The device or information that came with the device might also have information about the LLTD protocol or the network map.

A computer or device is not placed correctly on the map

This can occur for the following reasons:

  • The computer is running Windows 7 and is connected to a Public network. When a computer is on a Public network, Windows can't correctly place it on the network map. To fix this problem, you can try changing the network location to Home or Work, or connect to an existing Home or Work network. For more information about network locations, see Choosing a network location.

    Warning

    • When you connect to a Home or Work network, your computer becomes visible to other computers around you, which increases your risk of being exposed to malicious software from the Internet. You should only connect to Home or Work networks in places where you know and trust the people and devices on the network, such as your home or workplace. Avoid assigning the Home or Work network location to networks in public places, such as coffee shops, hotels, and airports.

  • The computer is running Windows XP and the LLTD protocol is not installed. Before a computer running Windows XP can be detected and placed correctly on the network map, you need to install the Link Layer Topology Discovery (LLTD) protocol on that computer. For more information about how to display computers running Windows XP on the network map, go to Network Map Does Not Display Computers Running Windows XP on the Microsoft website.

  • The device doesn't support the required protocols for Windows 7, which can cause some devices to appear on the network map, but not as you'd expect to see them. For example, a router could be shown as three things: a router, a switch, and an access point. Check the information that came with the device to see if it has a Windows 7 logo. If the device has the logo, it should appear correctly on the network map. The device or information that came with the device might also have information about the LLTD protocol or the network map.

A message is displayed which says that an error occurred during the mapping process

This can occur for the following reasons:

  • A computer or device on the network restarted during the mapping process. To fix this problem, wait for the computer or device to finish starting, and then refresh the network map by pressing F5.

  • Your computer is connected to a wireless network and the wireless signal quality is poor or intermittent. To fix this problem, move your computer closer to the wireless router or access point.

  • A device on the network, such as a hub or switch, is not working properly or is not compatible with the Link Layer Topology Discovery (LLTD) protocol, which Windows uses to create the map. To fix this problem, disable the device, turn it off, or remove it from your network.

  • Responses from other devices on the network are delayed or there is an incompatible router on the network. If responses are delayed, try waiting a few minutes and then refreshing the network map by pressing F5. If a router is incompatible, try disabling the router, turning it off, or removing it from your network.