HP OfficeJet Pro 6978 Error 0x6100004a Fixed but Now Only Printing Black? Here's What to Check

Question:
After resolving the HP OfficeJet Pro 6978 error code 0x6100004a (paper jam / printer failure), the printer is now working again. However, it only prints in black and white. Color printing no longer works despite trying different settings. What could be causing this issue and how can it be fixed?

Answer:

It's great to hear that you were able to resolve the HP error 0x6100004a, which is commonly associated with paper jams, carriage stalls, or internal sensor errors. However, the new issue-printing only in black and white-is actually quite common after a major fault or prolonged downtime. Let's walk through the most likely causes and solutions.

1. Check Print Settings (Most Overlooked Cause)

After resolving an error like 0x6100004a, printer settings can sometimes reset or default incorrectly.

• Go into your print dialog or driver settings

• Make sure "Color" is selected

• Disable "Print in Grayscale" or "Black Ink Only"

This setting alone can force black-only output even if your color system is working perfectly.

2. Inspect Ink Cartridge Status

The HP OfficeJet Pro 6978 uses four separate cartridges:

• Black

• Cyan

• Magenta

• Yellow

If any one of the color cartridges is empty, clogged, or not recognized, the printer may default to black-only printing.

Check:

• Ink levels via the printer screen or HP Smart app

• Any error messages related to cartridges

• Whether recently installed cartridges still have protective tape on vents

3. Print a Diagnostic / Quality Report

This step helps pinpoint which color is failing.

• From the printer menu, print a Print Quality Report

• Look for missing colors:

  • No cyan → cyan channel blocked

  • No magenta → magenta issue

  • Faded or streaky output → partial clog

This test gives you a clear direction instead of guessing.

4. Run Printhead Cleaning Cycles (But Don't Overdo It)

If your printer sat unused (especially after the 0x6100004a error), the printhead nozzles may have dried out.

• Run 1-2 cleaning cycles only

• Avoid running too many cleanings in a row (this wastes ink and can overheat components)

If colors start to return faintly, that confirms a clog issue.

5. Reseat and Inspect Cartridges

Remove and reinstall each color cartridge:

• Ensure proper seating

• Check vent holes (must not be blocked)

• Look for ink leakage or dried ink around contacts

A poorly seated cartridge can cause the printer to ignore that color entirely.

6. Possible Printhead Issue (More Serious)

If:

• All settings are correct

• Ink levels are good

• Cleaning cycles don't restore color

Then the issue may be with the printhead itself.

This can happen because:

• Ink dried inside the nozzles

• Air entered the ink system during the previous error

• Electrical failure in one or more color channels

At this point, deeper cleaning or printhead replacement-level service may be required.

About the Original Error (0x6100004a)

Just for context, error 0x6100004a is typically tied to:

• Carriage obstruction

• Paper jam sensors falsely triggered

• Encoder strip contamination

• Internal mechanical resistance

Fixing it often involves freeing the carriage or cleaning internal components-but that process can sometimes disturb ink flow or leave the printhead partially dried, which explains your current color issue.

Addressing printer problems can be tricky because they often require hands-on inspection and physical adjustments. Unfortunately, we're not able to provide remote repair services or step-by-step live troubleshooting. However, we do offer an in-person diagnostic and repair service through our facility at BCH Technologies Printer Repair Service (https://bchtechnologies.com/printer-repair-service). Due to high demand, we operate on a first-come, first-served basis, and it may take a few weeks before we can accept your printer.

Our services can target either full printer repair or specific components, with clear guidance throughout the process. That said, we understand our services may not be the most budget-friendly option. For that reason, we strongly encourage exploring self-help resources first. A great starting point is our YouTube channel homepage at BCH Technologies YouTube (https://youtube.com/@bchtechnologies). Use the search icon near the "About" section to find videos on specific topics. With hundreds of videos created over the years, this is the fastest way to locate relevant help-and YouTube may also suggest useful content from other creators.

Thanks again for your support and for sharing your experience. We're really glad the original issue is resolved, and hopefully, these steps will help you bring your color printing back to life!