Printer Pruner May Prune All the Print Queue Objects on Its Site

All of the PrintQueue objects published by print servers on the same site as a given domain controller (DC) may be detected as orphaned and deleted, even though the corresponding printers are available in the domain.

When this occurs, Printer Pruner writes a System event for each PrintQueue object that is detected as an orphan. This can accumulate rapidly for sites with large numbers of published print queues. If there are many published printers on the site, the System event log may become filled with Printer Pruner events.

Printer Pruner detects that a given PrintQueue object is orphaned by contacting the print server and comparing the Printer object to the Active Directory PrintQueue object. Because Printer Pruner runs only on DCs, if a DC is taken off the network, Printer Pruner is unable to contact any print servers and marks all published printers as being orphaned. By default, Printer Pruner deletes orphaned printers after checking three times, waiting eight hours between checks. Therefore, by default, a DC would have to be removed from the network and run continuously for at least 24 hours before PrintQueues objects are deleted.

NOTE: An incorrect Domain Name Server (DNS) or router configuration may also cause a DC to be unable to find print servers and exhibit this behavior.

To prevent incorrect printer pruning while a DC is removed from the network, use either of the following methods:

• Before removing a DC from the network for an interval longer than the Directory Pruning Interval and Directory Pruning Retry periods, set the Directory Pruning Interval value to Never. These policies are located in Group Policy Editor under Computer Configuration\Administrative Templates\Printers.
• Stop the Spooler service on the DC.

You can also allow the printers to be pruned and set the Check Published State policy for specific (or all) print servers in the domain. This policy causes the spooler on a print server to periodically verify that its published printers exist in Active Directory. By default, the Spooler service verifies the state of published printers only when it is started.

You should use the Check Published State policy only if network outages are common, because the widespread use of this policy on many computers in the domain (that are constantly checking the publication status of their PrintQueue objects in Active Directory) can adversely affect network performance. Microsoft recommends that you set this policy only on the main production print servers.

For infrequent outages involving DCs that last over 24 hours and leave the computer powered on for the duration of the outage, Microsoft recommends stopping the Spooler service on the DCs.

For additional informationabout using policies to control printers and Printer Pruner in Active Directory, click the article number below to view the article in the Microsoft Knowledge Base: