How To Troubleshoot HP Designjet Z6100 Printer Error 79-04


This article provides detailed solutions on HP Z6100 Printer error 79-04.

79-04 is a generic firmware error that is similar to a blue screen seen in Windows). It’s

shown if an unknown exception occurs that no specific printer subsystem can point to.


Generally, the error is caused by hardware problems, but often software or firmware issues are also responsible. So, the problem can be fixed by configuring a selection correctly or updating the printer’s firmware or software.

Job-related error

If a print job is incorrectly formatted for the printer, or printer doesn’t process the job correctly, the error can occur. This can be from 2 sources:

  • A PS job with commands that have wrong PS format
  • Issues related to job settings

When the error is caused by a job, there’s a problem with the printer’s firmware or there’s a defect in the job. For identifying the cause and solving it, the issue should be raised to the GBU via the GCC


The job must be sent via different settings. Often, the problem is caused by the combination of the job contents and specific settings.

If the file is sent straight to the printer, HP driver should be tried instead.

If a problem occurs while printing with the HP PostScript driver from an application with PS passthrough, the application’s options can be changed, so that PS is printed as a raster. The option can be found in the ‘Advanced’ options contained in the application’s printing dialog.

Data-related error

The hard disks and volatile memories in HP DesignJet printers have databases and files That can be changed with user data. Examples:

  • Printer’s queue
  • Hard partitions containing user jobs
  • Database storing printer settings.

When the printer starts it accesses some of this data. If any field has corrupt data or there are characters and values in the data that can’t be processed by the printer correctly, the error occurs.


As data is stored in RAM, EEROM or hard disk, replacing these physical components with new empty ones can fix such errors.

More effective solutions

1: All information entered by the user must be deleted with standard printer tools:

  1. All jobs in the queue must be deleted (from the front panel or EWS)
  2. Factory defaults must be reinstated to remove user configurations and calibrations
  3. Remove all non-standard paper presets from the printer that was created by the user or installed as OMES profiles via EWS or HP Printer Utility.

2:  If the problem wasn’t fixed by the previous step,  start printer with Diagnostics Boot mode and do an EEPROM reset.

3: If the previous step didn’t work, then go to the ‘Service Utilities’ menu, and then in ‘Secure Disk Wipe’ menu, set the level of ‘Sanitize’ to ‘Unsecure mode’.

Then, the Disk Wipe must be done, which will take about 47 minutes. It will clear all hard disk partitions containing user data, including the one where the operating system is installed. When the process is complete, a backup version of firmware will be installed from a backup partition, allowing the unit to start up.

As this firmware version is old, it should be upgraded to the current version after the printer restarts.

After this step, all 79-04 error caused by corrupt data will be fixed.

Network-related error

HP Designjet printers generally have inbuilt networking abilities. While network settings can be manually set, they are automatically got from the printer. These settings contain fields, such as IP address, subnet mask, host/domain names, etc.

If there are issues in the firmware, values in these fields can falsely interpret, causing the 79-04 error.


First, the network cable should be disconnected, so that the printer can be booted, and network settings changed.

Then, in the ‘Network Configuration’ menu in the front panel, all unused protocols, such as IPV6, SNMP and web services, must be disabled.

If this doesn’t work, the device must be manually configured:

First, the correct subnet mask and an IP within a valid range must be entered. Then, the same value as provided in the IP address field must be provided in the ‘Gateway’ filed. NO host/domain name should be set.

If the previous step doesn’t work, and a network is being used that is part of the printer, an accessory Jetdirect card should be used.

Concurrence issues and memory leaks

Sometimes 79-04 errors can occur at random due to heavy usage of the printer.  These are due to two causes:

Memory leaks: Before the execution of a program, memory is allocated. After the program is executed, allocated memory is freed up for use by other programs. If memory allocation isn’t properly programmed, whenever the program is executed, some memory will be incorrectly declared to be used or free. This is a memory leak.

When there’s heavy usage of a program with a memory leak, the memory increasingly turns full, as it isn’t freed correctly. When the leak is too big, the printer has no memory for carrying out new processes and then, a 79-04 error occurs

Concurrence issues: Some resources can be accessed by several programs or multiple executions of one program. This is known as ‘Multiple Threads’. Access to these resources must be handled correctly so that there’s no unexpected behavior. Problems arising out of improper control of such resources are called ‘concurrence issues’.


The primary cause must be identified and fixed in code; which requires the GBU’s intervention.

All options available for changing the user’s workflow must be tested and checked if a combination of the options can solve the issue.

In either case, very good understanding of the user’s workflow is required. Specifically, the following information is needed:

  • Settings of printer’s front panel
  • Application and RIP/driver being used
  • Settings of application/RIP/driver
  • Output files generated by the application, RIP or driver
  • Sample files that represent what the user is using
  • Operating system
  • Connection method with the printer
  • Description of normal flow when an error occurs and the frequency with which it occurs

When this information is available, replication of the environment is possible to find solutions. This information will also be required at the GBU for finding and rectifying the main cause of the error when it is notified.

Hardware-related error

Hardware usually doesn’t cause 79-04 error. Sometimes, a component failure in the printer’s electronics causes the error, as the printer’s electronics execute the firmware and process jobs. But it must be noted that hardware issues create specific errors that point out the failing component.


The following steps must be completed in the given order and every next step must be tried when the error hasn’t been fixed.

  1. The printer must be rebooted in Diagnostics Boot mode and the service tests executed to check that all electronic components are working:

Troubleshooting steps for data-related system errors must be taken.

  1. Memory must be replaced
  2. HDD must be replaced
  3. The problem must be escalated before any additional parts are replaced

HP Technical Support – Scope of Service

If you are unable to solve the error, then please contact our HP technical support helpdesk team at this number ✆+1-800-828-6304. Our HP tech support team can assist you by

  • Providing 24X7 help
  • Solving problems through chat
  • Replying to your e-mail queries
  • Helping you on the phone

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