JSI Tip 2957. Windows NT 4.0 issues Error 85: local device is already in use?

When you try to use a NET USE command to connect to a local LPT port, you receive:

Error 85: local device is already in use.

This will happen if the LPT port is connected to a printer share.

To fix the problem:

1. Determine if the LPT port is connected to a printer share by opening a CMD prompt and typing:

    NET USE.

2. If the port is connected to a print share, type:

    NET USE LPT /D

    where is the port number.

3. Issue the original NET USE LPT \ command.