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size-error

Brother MFC-L8900CDW: Size Error

Verified with sources1 sourceReviewed Aug 23, 2026
Technician coming? See what they must show you
Home office laser multifunction printer
Túllio FCC BY-SA 4.0Image source

Risk level

Medium

Proceed carefully and stop if the check is unclear.

Urgency

High

Quick answer

Brother defines “Size Error” as: The driver-selected paper size is unsupported by the selected tray. That message alone does not prove a replacement part. The next useful discriminator is job-requested size, selected tray capability and the actual loaded sheet dimensions.

Safety first

Stop and check this first

  • Use only media and sizes supported by the selected tray and duplex path.

Safe checks you can perform

  • Preserve the exact display and context
  • Run one controlled owner-safe discriminator
  • Stop at the proved owner/service boundary

Leave these tasks to a qualified professional

  • Do not attempt this professional task: Measured handoff for Size Error

What a technician must be able to justify

Technician visit

These are the steps they must carry out and show you. Tick them as they work: if steps are skipped, do not accept a part swap.

These are not instructions for opening or handling the equipment yourself. They are the checks that should support a technical conclusion.

  1. Measured handoff for Size Error

    What they doCompare job ticket, tray settings and measured sheet, then test the relevant size/type sensors and registration timing before replacing hardware.

Before accepting a part or repair

Nothing has been shown yet. Do not accept a part swap based on the code alone.

Follow these steps

Note: Follow the documented order. An error code identifies the affected system, but it does not prove by itself which part has failed.

  1. Preserve the exact display and context

    No special tools

    Photograph “Size Error”, including any tray, color or ## suffix. Save model/region, page count, supplies-life page, job/media and the last intervention before clearing it.

    Use only media and sizes supported by the selected tray and duplex path.

    Evidence: Brother MFC-L8900CDW Online User's Guide - error and maintenance messages

  2. Run one controlled owner-safe discriminator

    No special tools

    Record the job-requested size/type, tray-configured size/type and actual sheet dimensions/media. Correct only the mismatched layer and retest one sheet. Record job-requested size, selected tray capability and the actual loaded sheet dimensions; change only one variable before retesting.

    Use only media and sizes supported by the selected tray and duplex path.

    Evidence: Brother MFC-L8900CDW Online User's Guide - error and maintenance messages

  3. Stop at the proved owner/service boundary

    No special tools

    A mismatch between those three values is configuration/media, not hardware. If all agree and the message repeats, service the size/type sensing and registration branch.

    Use only media and sizes supported by the selected tray and duplex path.

    Evidence: Brother MFC-L8900CDW Online User's Guide - error and maintenance messages

Still not solved

If the error persists, stop here. See what the technician must do and show you.

Where this code applies

A code is meaningful only inside the right product and version context.

Primary scope

System
Printers
Brand
Brother
Product type
Laser printer

Known code variants

  • Brother Erreur format
  • Brother Error de tamaño
  • Brother Errore formato
  • Brother Formatfehler
  • Brother Size Error
  • Erreur format
  • Error de tamaño
  • Errore formato
  • Formatfehler
  • MFC-L8900CDW Erreur format
  • MFC-L8900CDW Error de tamaño
  • MFC-L8900CDW Errore formato
  • MFC-L8900CDW Formatfehler
  • MFC-L8900CDW Size Error
  • Size Error

What it means

Official meaning: The driver-selected paper size is unsupported by the selected tray. Decision boundary: record job-requested size, selected tray capability and the actual loaded sheet dimensions. Service or purchase proof: Compare job ticket, tray settings and measured sheet, then test the relevant size/type sensors and registration timing before replacing hardware.

Warnings and stop conditions

  • Mediumsource verified

    Use only media and sizes supported by the selected tray and duplex path.

    Evidence: Brother MFC-L8900CDW Online User's Guide - error and maintenance messages

Symptoms and causes

Probable causes · in order

  • What the Brother message establishesConfirmed

    The official Brother MFC-L8900CDW family guide defines “Size Error”: The driver-selected paper size is unsupported by the selected tray.

    Evidence: Brother MFC-L8900CDW Online User's Guide - error and maintenance messages

  • The observation that changes the next branchPossible

    Capture job-requested size, selected tray capability and the actual loaded sheet dimensions. A mismatch between those three values is configuration/media, not hardware. If all agree and the message repeats, service the size/type sensing and registration branch.

    Evidence: Brother MFC-L8900CDW Online User's Guide - error and maintenance messages

Virtual technician

Does size-error still appear after these checks?

Answer a few questions to narrow down the likely cause and the safest next action. Guidance only - it never replaces a professional.

Sources and technical references

  1. 1
Sources: Brother MFC-L8900CDW Online User's Guide - error and maintenance messagesreviewed 2026-08-23 · verified

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