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Cannot Map LPT1 on Windows XP/Vista

In Windows XP Service Pack 2/Vista/2008, if you attempt to map a parallel port with NET USE (eg NET USE LPT1 \\SERVER\QUEUE), you receive the following error:

    The password is invalid for \\server\queue.
    Enter the user name for 'server':

This occurs because under these operating systems, non-administrators cannot map an LPT port which already exists as a physical port (usually LPT1).

In Windows XP, one solution is to grant the user local administration rights. In Windows Vista/2008, this does not work because users with local administration rights are not granted those rights unless they elevate specific tasks with User Account Control (UAC). But even that does not work because a command prompt or script which is elevated with UAC runs under a different context to the logged-in user, so the mapped port is not available to other applications. So the only way to map a port is via the same process which runs the application requiring the mapped port, which will lose the user's mapped drives. So there are a number of complications. However, if the user is granted local administration rights, and UAC is disabled, the NET USE command works properly for the logged-in user.

But a more elegant solution which enables NET USE to operate as expected in any configuration is to disable the hardware port:

Windows Vista/2008

  1. Right-click Computer on the desktop and choose Properties.

  2. Click Device Manager.

  3. Click the + next to Ports (COM & LPT).

  4. Right-click ECP Printer Port (LPT1) and click Disable.

  5. Choose Yes when prompted.

  6. Close Device Manager.

Windows XP

  1. Right-click My Computer on the desktop and choose Properties.

  2. Click the Hardware tab.

  3. Click Device Manager.

  4. Click the + next to Ports (COM & LPT).

  5. Right-click ECP Printer Port (LPT1) and click Disable.

  6. Choose Yes when prompted.

  7. Close Device Manager.

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