Printing issues with 4x6 labels when using a Datamax MK III label printer with SendPro Online

Learn how to resolve an issue with Datamax MK III label printer not printing 4x6 inch shipping labels when using SendPro Online.
Products affected: SendPro® Online


The Datamax MK III printer will not print labels.


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


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 installed

With the roll sitting between the two green pressure brackets, make sure of the following:
  • The roll feeds from the top
  • The labels are facing up and the glossy backing paper is facing down
  • 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: Run a test print

  1. Select the Windows Start > 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.

Note: These steps work for most ink or laser printers.

  • If cannot run a test print from the printer, then the issue is with the printer, not with SendPro Online. Contact your local IT department or the printer manufacturer.
  • If the test print works from the printer, but you cannot print from SendPro Online, then the issue is with SendPro Online.

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.

UPDATED: August 14, 2021

Contact Us
Live Chat
Available • Closes at 8pm ET
Sales team hours are 8am-6pm ET
Live Chat
Live Chat is currently unavailable.
Chat is available Mon-Fri, 8am-8pm ET
Create a case
Submit support requests (Sign in required)