Zebra ZD421 driver for Mac and Windows: install and test

You don't need to download a Zebra ZD421 driver for Mac. Zebra recommends the CUPS driver that comes with macOS, which you select as Zebra ZPL Label Printer when you add the printer. On Windows you install the ZDesigner Windows Printer Driver v10 from Zebra's ZD421 support page.

This guide covers both, shows how to find the printer's IP address and test the printer, and then explains how to add the ZD421 to Spooler if you print labels from Afosto.

Which Zebra ZD421 drivers you need

The support page covers all three models: the ZD421D (direct thermal), the ZD421T (thermal transfer) and the ZD421C (ribbon cartridge). Download the Windows driver from zebra.com only, not from driver download sites.

Before you start: connect the printer and find its IP address

Load the labels, and on a thermal transfer model the ribbon, then close the cover and switch the printer on. Wait until the STATUS light is solid green.

As standard, you connect the ZD421 to a computer by USB. A network connection needs the Ethernet (LAN) module or the Wi-Fi option, which Zebra fits at the factory or you add later. To print from Spooler, the printer has to be on your network.

For the network setup of a Wi-Fi model, use the Zebra Printer Setup Utility app (Android and iOS) or Zebra Setup Utilities on Windows. Both walk you through the wireless settings.

Bought your ZD421 in Europe, the Middle East or Africa on or after 1 August 2025? To meet the EU Radio Equipment Directive, these printers ask you to set a Protected Mode password and a front panel password during setup. Until then you can't change some settings. Zebra explains this on the ZD421 support page.

Print a configuration report

The configuration report (also called the configuration page or configuration label) lists the printer's settings and its network address. To print the configuration page on a ZD421:

1. Make sure labels are loaded and the STATUS light is solid green.

2. Press and hold FEED and CANCEL together for two seconds, then release.

3. The printer prints a printer configuration report. With a network option installed, a network configuration report follows.

4. On the network report, find the IP ADDRESS line for your connection, wired or wireless. You need this address in the next steps.

Give the printer a fixed IP address: a static address set with Zebra Setup Utilities, or a reservation in your router. If the address changes, your computer can no longer reach the printer.

Zebra ZD421 driver: Mac

There is no Zebra ZD421 Mac driver to download. According to Zebra's support article, Zebra doesn't issue downloadable Mac drivers for its label printers and recommends the CUPS driver that macOS already includes. That goes for any Zebra printer driver for Mac: you pick the printer language, ZPL for the ZD421, instead of a model.

Add the ZD421 over the network

1. Open System Settings and click Printers & Scanners in the sidebar.

2. Click Add Printer, Scanner, or Fax.

3. Click the IP button at the top of the window.

4. Fill in the fields:

   • Address: the IP address from the configuration report, for example 192.168.1.50
   • Protocol: HP Jetdirect - Socket
   • Queue: leave empty
   • Name: something you recognise, such as Zebra ZD421
   • Use: choose Select Software and pick Zebra ZPL Label Printer from the list

5. Click Add.

Zebra's CUPS guide connects network printers this way, with a socket connection on port 9100, the default for Zebra desktop printers. If the socket connection doesn't work on your network, add the printer again and choose Line Printer Daemon - LPD as the protocol. Apple describes the fields in Add and manage printers on Mac.

Add the ZD421 by USB

Connect the printer with a USB cable and switch it on. In Printers & Scanners, click Add Printer, Scanner, or Fax and select the ZD421 in the list. Under Use, choose Select Software, pick Zebra ZPL Label Printer and click Add.

Is Zebra ZPL Label Printer missing from the list? Zebra advises a system update that includes the CUPS driver, so update macOS and try again.

Test the printer on a Mac

Send the ZPL command ~WC through the new printer. The ZD421 answers with a configuration report, which shows that your Mac reaches it. Open Terminal and list your printers:

lpstat -p

Then send the command to the ZD421, using its name from that list:

echo "~WC" | lp -d Zebra_ZD421 -o raw

Prefer not to use Terminal? Open a PDF in Preview, for example a shipping label, and print it to the ZD421.

Zebra ZD421 driver: Windows

On Windows you use Zebra's ZDesigner Windows Printer Driver v10. It supports Windows 10 and Windows 11. In the wizard, the printer appears as ZD421-203dpi ZPL or ZD421-300dpi ZPL, depending on the resolution of your model.

Install the driver before you connect the printer by USB. If you connect it first, Windows may list it as an unspecified device (see Troubleshooting).

Download and install the ZDesigner driver

1. Go to the ZD421 support page and open the Downloads tab. The Zebra ZD421 driver download is listed as Windows Printer Driver v10. Accept the licence agreement to start the download.

2. Run the downloaded file as administrator, as Zebra advises, and click Yes when Windows asks for permission.

3. Follow the wizard, choose Install Printer Driver and accept the licence terms.

4. Choose the connection:

   • Network Port for Ethernet or Wi-Fi. The wizard scans your network. Select the ZD421 by its IP address and click Add.
   • USB Port for a USB cable. Connect the printer when the wizard asks, and the wizard detects the model.

5. Choose the printer name and the language ZPL, then click Install.

Is the ZD421 missing from the network scan? Choose Manual, select your model and create a new network port. Enter the IP address as both the port name and the printer name. Zebra shows every screen in Install Zebra printers using ZDesigner driver v10.

Test the printer on Windows

Open the Printer properties of the ZD421 and click Print Test Page on the General tab. You can also print a configuration label from Zebra Setup Utilities: select the printer, click Open Printer Tools, choose Print configuration label on the Print tab and click Send.

Add the Zebra ZD421 to Spooler

Spooler is the print service of Afosto. It sends labels, packing slips and receipts from Afosto to your printers, through a Spooler hub on your network or through Spooler Desktop, an app for Windows and Mac. Spooler is included in every paid OMS package, and label printers such as the ZD421 use ZPL.

With Spooler Desktop, you first add the ZD421 to the computer as described above. Then:

1. Install Spooler Desktop on that computer and sign in, as described in Spooler Desktop. You request the sign-in details from Afosto support.

2. Open Spooler Desktop. On a Mac, click the Spooler icon in the menu bar and choose Open Spooler.

3. Go to the Printers tab. The ZD421 appears under the name you gave it, with the status Online.

4. Check that the box in the Active column is ticked. Only active printers are available through Spooler. With Printers active by default switched on, every new printer is active straight away.

The ZD421 is now available to Afosto through Spooler. In the WMS app, for example, the shipping label comes out of the label printer at the last scan when that setting is on. Every print job appears in the Spooler jobs overview, where you can run it again with one click.

Using a Spooler hub instead

With a Spooler hub, you don't install a driver on a computer. You add the ZD421 in Spooler with the encoding ZPL, let the hub scan the network for the printer and test the connection with a test print. The steps are in Add a printer.

Troubleshooting

Windows shows the ZD421 as an unspecified device

You connected the printer by USB before you installed the driver. Zebra's fix: switch the printer off, open Device Manager and uninstall USB Printing Support. Install the ZDesigner driver, then switch the printer on and connect it again.

Labels are skipped or print across the gap

Run a SmartCal media calibration. With the STATUS light solid green, press and hold PAUSE and CANCEL together for two seconds. The printer feeds a few labels and measures them. Repeat this when you switch to labels of another type or size.

The label comes out blank

The labels probably don't match the print method. Without a ribbon, the ZD421 prints only on direct thermal labels. Zebra's scratch test tells them apart: drag a fingernail firmly across the label. A black mark means direct thermal labels; no mark means thermal transfer labels, which need a ribbon on a ZD421T or ZD421C.

Labels look grainy

In Spooler Desktop, open the Printers tab and change Default printing backend from Engine7 to Engine5.

The ZD421 doesn't appear in Spooler Desktop

Check that the printer is added to the computer where Spooler Desktop runs, and that a test print from that computer works. Then check the box in the Active column. For more checks, see Spooler troubleshooting.

Printing stopped after a restart of the router or printer

The printer has probably received a new IP address. Print a configuration report, add the printer again with the new address and give it a fixed IP address.