Err Msg: A Duplicate Name Exists on the Network...

• Microsoft Windows NT operating system version 3.1
• Microsoft Windows NT Advanced Server version 3.1

SYMPTOMS

With Windows NT, multiple network adapters in one machine must be on different networks (either physically separate networks or different logical networks with different transport protocols). Otherwise, you will receive the following error message:

   A duplicate name exists on the network. This error prevented the
   network from starting.

CAUSE

The duplicate name exists on the network error occurs because each adapter will attempt to register itself on the network using a NetBIOS name. When the adapters try to register their NetBIOS names on the network, only the first adapter that attempts to register its NetBIOS name will succeed. The second adapter's attempt to register its name will generate the error message above and fail to register.

Windows NT does not check for these potential conflicts when a second network adapter is installed. Windows NT simply binds all installed protocols to the second adapter, regardless of whether they were bound to the first network adapter.

RESOLUTION

To work around this error, either manually disable the bindings or remove the conflicting protocol from the second network adapter. This can be done using the Network option in Control Panel