setup keeps failing when i try to install the software, it just hangs or says 'communication error'

Diagnosis

The communication error during the HP LaserJet Pro M404dn setup is typically caused by a "handshake" failure between the HP Smart/Easy Start installer and the printer's network interface. This happens because the modern HP installation wrappers attempt to perform a pre-installation scan of the network using specific UDP ports that are frequently blocked by Windows Defender Firewall or third-party antivirus suites (like Norton or McAfee). When the software cannot "see" the printer despite it being powered on, the installer hangs indefinitely or triggers a generic communication timeout. Furthermore, if you have previously attempted to install the printer, Windows may have automatically assigned a generic "Class Driver" to the device. This creates a driver conflict where the full software suite tries to overwrite a locked system file, resulting in a failure. You can confirm this by checking the "Devices and Printers" menu in the Control Panel; if the M404dn appears with a yellow exclamation mark or is listed as an "Unspecified" device, the communication bridge is broken at the OS level.

How to Fix It

To bypass the unstable "Easy Start" wrapper and establish a direct connection, follow these precise steps to perform a manual driver injection:

1. Disconnect the USB cable from the printer to your PC (if applicable) and turn the printer off.
2. Open the Control Panel, navigate to Programs and Features, and uninstall any software starting with "HP LaserJet Pro M404" or "HP Easy Start."
3. Restart your computer to clear the print spooler cache.
4. Navigate to the official HP Driver site and avoid the "Smart" app. Search specifically for the HP LaserJet Pro M404dn Full Software and Drivers package (the standalone .exe file, typically around 150MB-200MB).
5. Right-click the downloaded .exe file and select "Run as Administrator." This is critical to allow the installer to modify the system registry and open firewall ports.
6. When the installation reaches the "Connection Type" screen, do not select "Automatic." Manually select "USB" if using a cable, or "Wired Network" if using Ethernet.
7. If using a network connection, enter the printer's static IP address manually (found by printing a Configuration Page from the printer's onboard menu: Reports > Config Report).
8. Complete the wizard and restart the PC one final time before printing a test page.

If That Didn't Work

• Manual Port Addition: If the software installs but cannot communicate, go to Printer Properties > Ports > Add Port. Select "Standard TCP/IP Port," click "New Standard TCP/IP Port," and enter the printer's IP address. This bypasses the HP discovery service entirely.
• Disable IPv6: On the printer's physical control panel, go to Network > TCP/IP > IPv6 and set it to "Off." Many Windows 10/11 environments struggle with IPv6 priority, causing the installer to hang while waiting for a response that never comes.
• USB Cable Validation: Ensure you are using a high-speed USB 2.0 cable shielded with ferrite beads (the small cylinders near the ends). The M404dn is sensitive to signal noise; cables longer than 6 feet (2 meters) often cause the "communication error" during the driver handshake phase.
• Clear Print Spooler: Open the "Services" app (services.msc), find "Print Spooler," right-click it and select "Stop." Navigate to C:\Windows\System32\spool\PRINTERS and delete all files in that folder. Restart the Print Spooler service and try the installation again.

Heads Up

• Avoid using USB hubs or docking stations for the initial installation; plug the printer directly into a motherboard USB port.
• Set a Static IP address on the printer via the embedded web server (EWS) to prevent the "Printer Offline" error that occurs when the DHCP lease expires.
• Disable "Fast Startup" in Windows Power Options if the printer is not detected after a reboot, as this can prevent the USB controllers from fully resetting.
• Always update the printer's internal firmware via the EWS before installing the latest PC drivers to ensure compatibility with the latest security protocols.