HP LaserJet Pro MFP M126fn Stuck on “Initializing” and Showing “Install Black Cartridge” – Troubleshooting Guide – Bison Knowledgebase

HP LaserJet Pro MFP M126fn Stuck on “Initializing” and Showing “Install Black Cartridge” – Troubleshooting Guide

📅 27 Jan 2026 📂 General 👁 7 views

HP LaserJet Pro MFP M126fn is a monochrome laser all-in-one printer designed for small offices and home offices. It supports printing, scanning, copying, and faxing with reliable laser output and standard USB/LAN connectivity.

Key Features

Monochrome laser printing
Print, Scan, Copy, Fax (All-in-One)
Uses HP 83A (CF283A) black toner
USB and Ethernet connectivity
Compact design for small offices

Introduction

A common field issue with the HP LaserJet Pro MFP M126fn is the printer getting stuck on “Initializing” and later displaying “Install Black Cartridge”, even when a cartridge is already installed. This article explains the root causes, technical background, and step-by-step resolution to restore normal printer operation.

Problem Description

Symptoms

Printer displays Initializing for a long time
Error changes to Install Black Cartridge
Printing, scanning, and copying are disabled
Issue may appear after toner replacement or power outage

Technical Explanation

During startup, the printer firmware performs a cartridge presence and chip authentication check. The error occurs when:

Cartridge chip is not detected
Electrical contacts between cartridge and printer are faulty
Protective seals interfere with detection
Cartridge sensor or DC controller fails

If the check fails, initialization halts and the printer requests cartridge installation.

Common Root Causes

Cause Description
Cartridge not seated properly Misalignment prevents chip contact
Dirty contacts Toner dust blocks electrical signals
Refilled / compatible toner Chip incompatibility or failure
Protective seal left inside Sensor obstruction
Faulty toner cartridge Dead or damaged chip
Printer hardware fault Cartridge sensor or controller board

Cause	Description
Cartridge not seated properly	Misalignment prevents chip contact
Dirty contacts	Toner dust blocks electrical signals
Refilled / compatible toner	Chip incompatibility or failure
Protective seal left inside	Sensor obstruction
Faulty toner cartridge	Dead or damaged chip
Printer hardware fault	Cartridge sensor or controller board

Step-by-Step Troubleshooting & Resolution

Step 1: Perform Power Reset

Turn OFF the printer
Remove power cable from printer and wall socket
Wait 2–3 minutes
Power ON the printer without the cartridge
When prompted, insert the toner cartridge

Step 2: Reinstall the Toner Cartridge

Open the front cover
Remove the black toner cartridge
Gently shake it left and right
Reinsert firmly until seated correctly
Close the cover completely

Step 3: Verify Protective Seal Removal

Ensure all orange tapes and plastic seals are removed
Even partial tape residue can cause detection failure

Step 4: Clean Cartridge & Printer Contacts

Required tools:

Lint-free dry cloth or isopropyl alcohol (IPA)

Procedure:

Clean metal contacts on toner cartridge
Clean spring-loaded pins inside printer
Allow surfaces to dry fully before reinserting

⚠️ Do not use water or excessive force.

Step 5: Test with Known-Good Toner

Prefer original HP 83A (CF283A) cartridge
If alternate cartridge works → original cartridge is faulty

Step 6: Cold Reset (If Needed)

Turn OFF printer
Hold Cancel (X) + Right Arrow
Turn ON printer
Release buttons when HP logo appears

Diagnostic Matrix

Test Result Conclusion
Another cartridge works Original cartridge defective
No cartridge detected Printer hardware issue
Error after refill Chip incompatibility
Works after cleaning Contact contamination

Test Result	Conclusion
Another cartridge works	Original cartridge defective
No cartridge detected	Printer hardware issue
Error after refill	Chip incompatibility
Works after cleaning	Contact contamination

Common Issues & Fixes

Issue Fix
Refilled toner not detected Replace with original cartridge
Error after power surge Perform cold reset
Repeated initialization loop Clean contacts, test toner
Message persists with original toner Service intervention required

Issue	Fix
Refilled toner not detected	Replace with original cartridge
Error after power surge	Perform cold reset
Repeated initialization loop	Clean contacts, test toner
Message persists with original toner	Service intervention required

Security & Safety Considerations

Always power OFF before handling toner
Avoid touching electrical contacts with bare hands
Do not insert damaged or leaking toner cartridges
Use genuine consumables to prevent firmware or hardware damage

Best Practices

Use original or high-quality compatible toner
Clean cartridge area during every toner replacement
Avoid frequent power fluctuations (use UPS)
Store toner in dry, dust-free conditions
Replace toner before it is fully depleted

When to Escalate for Repair

Escalate to authorized service center if:

Original toner is not detected
Cleaning and reset do not resolve issue
Printer shows error without any cartridge installed

Likely components:

Cartridge sensor
DC controller board

Conclusion

The “Initializing” followed by “Install Black Cartridge” error on HP LaserJet Pro MFP M126fn is primarily caused by toner cartridge detection failures. In most cases, reseating, cleaning contacts, or replacing a faulty cartridge resolves the issue. Persistent errors with original cartridges indicate hardware-level faults requiring professional repair.

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