LPR Printers Show Status Unknown

Article translations Article translations
Article ID: 163241 - View products that this article applies to.
This article was previously published under Q163241
This article has been archived. It is offered "as is" and will no longer be updated.

IMPORTANT: This article contains information about editing the registry. Before you edit the registry, make sure you understand how to restore it if a problem occurs. For information about how to do this, view the "Restoring Registry" Help topic in Regedit.exe or the "Restoring a Registry Key" Help topic in Regedt32.exe.
Expand all | Collapse all


When you print to a printer through a line printer remote (LPR), the status of the printer may show "Status Unknown" in Windows NT 3.51.

When the printer is opened from the Printers folder in Windows NT 4.0, the printer may show <Failed to open, Retrying> and the Properties for that printer may be unavailable.

If you attempt to add an LPR port, which does not appear in the list of ports but actually exists in the registry, the follow error may occur:
The port already exists.
Additionally, all available LPR ports may not be listed from within Printer Properties Details or Ports tabs.


There are two known possible causes for these symptoms:
  • An invalid LPR Port registry entry.

    An invalid registry entry could be caused by manually adding an LPR port with Registry Editor. If the manually added port is missing values, it can cause the above error. It is recommended that an LPR port only be added through the user interface through the Print Manager Printers folder.
  • The "\" character was used in the LPD queue name.

    If the "\" character is used anywhere in the line printer daemon (LPD) queue name (name of printer on that machine providing LPD), an additional subkey is added under the name of that port in the registry. This precludes Print Manager or Printers folder from successfully parsing any ports listed below the port with the invalid character in the name.


To fix the problem, the invalid port must be removed from the registry. To do this, use the following steps:
  1. Click the Start button, point to Settings, click Control Panel, and then double-click the Services icon.
  2. Select Spooler from the list of services, then click Stop.
WARNING: Using Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk.

For information about how to edit the registry, view the "Changing Keys And Values" Help topic in Registry Editor (Regedit.exe) or the "Add and Delete Information in the Registry" and "Edit Registry Data" Help topics in Regedt32.exe. Note that you should back up the registry before you edit it.
  1. Run Registry Editor (Regedt32.exe) and locate the following key:
    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Print\Monitors \LPR Port\Por

    NOTE: The above registry key is one path; it has been wrapped for readability.
  2. Locate any ports with a "\" character in the name or ports that are missing entries. In the most obvious case, the IP port will not have any values or will only have values that were added manually.

    NOTE: Normally the LPR port will have a name that is either the IP address or the DNS name of the destination host providing LPD service
  3. With the invalid port selected, click the Edit menu, then click Delete.
  4. Quit Registry Editor.
  5. Click the Start button, point to settings, click Control Panel, and then double-click the Services icon.
  6. Select Spooler from the Services list, and then click Restart.


Windows NT supports TCP/IP printing as documented in RFC 1179. During the creation of an LPR port, an IP address (name or address of host providing lpd:) and LPD queue name (name of printer on that machine:) must be provided for the print destination.

The following are examples of valid and invalid LPR Port entries:

Valid LPR Port:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Print\Monitors \LPR Port\Ports\\Timeouts

Invalid LPR Port:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Print\Monitors \LPR Port\Ports\\&lt;additional_name&gt;\Timeouts


Microsoft has confirmed this to be a problem in Windows NT version 3.51 and 4.0. We are researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.


Article ID: 163241 - Last Review: February 24, 2014 - Revision: 2.1
  • Microsoft Windows NT Workstation 3.5
  • Microsoft Windows NT Workstation 3.51
  • Microsoft Windows NT Workstation 4.0 Developer Edition
  • Microsoft Windows NT Server 3.5
  • Microsoft Windows NT Server 3.51
  • Microsoft Windows NT Server 4.0 Standard Edition
kbnosurvey kbarchive kbbug kbpending kbprint KB163241

Contact us for more help

Contact us for more help
Connect with Answer Desk for expert help.
Get more support from smallbusiness.support.microsoft.com