Printing issues with 4x6 labels with Datamax MK III label printer in SendPro Online

Products affected: SendPro® Online


The Datamax MK III printer will not print labels.


There is an issue with the Datamax MK III printer or an issue in the Windows operating system.


UPDATED: June 30, 2020

Solution 1: Ensure that the printer driver is installed

See Installing the Datamax Mark III printer for SendPro Online in Windows.

Solution 2: Ensure that the roll in the Datamax MK III printer is correctly seated

With the roll sitting between the two green pressure brackets, make sure of the following:
  • Roll is seated to feed from the top
  • Adhesive sticker side of the roll is face up and visible
  • Glossy side of the roll, which gets discarded after a print, is face down and not visible
  • Roll feeds under the two green guides
  • Leading end of the roll rests on the black and green roller inside the printer
If the leading end of the roll sticks out of the printer when the cover is closed, press start/pause on the cover of the printer once. This causes the leading end of the roll to position itself at the end of the container.

SendPro Online Datamax Mark III printer rollers

Solution 3: Determine if there is an issue with SendPro by running a test print

  • If you are able to test print from the printer itself, but unable to print in SendPro, the printing issue is with SendPro.
  • If you are unable to test print from the printer itself, the printing issue is not with SendPro. Contact your local IT department or the printer manufacturer.
Follow these steps to perform a test print (these steps apply to most ink or laser printers):
  1. Select the Windows Start icon > Devices and Printers.
  2. Right-click the Datamax-ONeil Mark III printer and select Printer Properties.
  3. Select the General tab.
  4. Select Print Test Page.

If print quality is poor:

  1. Click Windows Start.
  2. Open Control Panel.
  3. Right-click on the Datamax MK III printer and choose Printer Preferences.
  4. Click the Graphics tab.
  5. Set Dithering to None.
  6. Click OK.