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Jobs submitted to the Loftware Print Server (LPS) are failing.  The LPS Status Client displays the following error message:

(M4756) _PRINTERNUMBER value is not valid! (M4757) The number is outside the key limit or the VisibleQueues setting the llmwdn32.ini [Private] section!

Example Screenshot 1


Looking at Example Screenshot 1, the Status Client indicates this LPS has 50 printer seats ( PW-LPS [50] [4] [1] ), however the Printer Number specified in the print request is 51 ( _PRINTERNUMBER="51"). 

While it is possible that an invalid printer number may have been specified in the print request, a more common cause is that the number of print seats in the LPS license was recently increased, but the Loftware Print Server service has not been restarted. In order to recognize license changes, the LPS service must be restarted. 

When Design 32 is launched, it checks the current license string, which can be displayed by clicking Help > About Loftware Label Manager.

In Example Screenshot 2, we see that the number of Printer Seats recognized in the license is 55, however in Example Screenshot 1 of the LPS Status Client from the same LPS system, the number of print seats is 50. This difference serves as an indicator that the license string was recently modified but the LPS service has not been restarted since the license change.

Example Screenshot 2


  1. If the printer number specified in the print request sent to the LPS is greater than the number of print seats available in the license and no additional print seats have been added to the license, then this failure should be discussed with the person or application support personnel for the application which generated the print request.

  2. If the number of print seats in the license has been recently increased, restart the LPS service for this change to be recognized by the LPS.



Article Number



Loftware Print Server 9.x and higher


Any supported LPS family product environment