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Joe B.

Reviewed for technical accuracy

Specialities: Paper size mismatches (A4 vs Letter), printer driver and print dialog checks, Windows & macOS page setup settings, tray selection issues.

What to check first (safely): print dialog paper size, tray selection, and driver defaults

Technician avatar Technician
Got it — “Letter instead of A4” can be surprisingly stressful, especially when documents suddenly look cut off or shifted.

Let’s start with the safest checks first. I don’t want you changing anything that could scramble your printer setup.

Two quick questions so we narrow this down:
1) Are you printing from Windows, a Mac, or a phone/tablet?
2) What app are you printing from — a PDF viewer, Word, a browser, or email?
Customer
Windows laptop. Mostly printing PDF files and sometimes Word. It used to be fine, and now it keeps coming out on Letter.
Technician avatar Technician
Thank you — that helps. When it “used to be fine” and then changes, it’s often a setting in one of three places:
• the app (PDF/Word)
• the Windows print dialog
• the printer driver default

Before we touch anything: do you remember if anything changed recently — a Windows update, a new printer install, switching printers, or printing from a different app?
Customer
Windows updated last week. Also my neighbor helped me “re-add” the printer because it wasn’t showing up one day.
Technician avatar Technician
That’s a strong clue. Re-adding a printer can sometimes install a “generic” driver or reset defaults back to Letter (common in the U.S.).

Let’s do a no-risk observation first: when you open the print window (Ctrl+P), what does it show for Paper size right now — A4, Letter, or something else?
Customer
It shows Letter. I tried changing it to A4 once, but it went back the next time.
Technician avatar Technician
You’re not imagining it — that “changes back” pattern usually means the default is coming from the driver or the app’s own saved settings.

I want to keep this safe: we’re not doing any resets, and we’re not deleting anything yet.

Next check: in that same print window, do you see an option like “Choose paper source by PDF page size” or “Auto select” for tray/source?
Customer
In the PDF program I see something like “Choose paper source by PDF page size.” I don’t know what it means, so I left it alone.
Technician avatar Technician
Good call leaving it alone. That option can be helpful, but it can also surprise people if the PDF is tagged as Letter even when it “looks like” A4.

Safe question (no clicking required): are you printing PDFs you downloaded from a website, or PDFs you created/scanned yourself?
Customer
Mostly downloaded PDFs—forms and invoices. Some are from email attachments.
Technician avatar Technician
That fits. Some documents are built as Letter, even if you’re in an A4 country. Then the printer follows what the file requests.

Let’s separate two situations (this prevents “guessing”):
• If you print from Word, does it also default to Letter?
• Or is it only happening in PDFs?
Customer
Word seems okay sometimes. PDFs are the worst—either it prints Letter or it cuts off the bottom.
Technician avatar Technician
That’s very common with PDFs. And I’m glad you mentioned “cuts off the bottom” — that usually points to a mismatch between:
• what the file is asking for (Letter vs A4), and
• what the printer tray actually has loaded

A safe thing to check: on the printer itself, does the paper tray have an adjustable guide, and is it set snugly to A4? (No need to force anything—just a gentle look.)
Customer
The guides are set for A4, yes. I only use A4 paper. The printer is a Brother.
Technician avatar Technician
Perfect — and thanks for the brand. With Brother printers, paper size can be “remembered” in a few different places depending on how it was installed.

Trust moment: I don’t want you changing the printer’s panel settings unless we’re sure it’s needed, because that can be confusing and easy to undo incorrectly.

Safer check on the computer: when you choose the printer in Windows, do you see multiple entries (like “Brother (Copy 1)” or “Brother – Driver”)?
Customer
Yes! I see two similar Brother printers. One says something like “(Copy 1)”.
Technician avatar Technician
That explains a lot. “Copy 1” often appears after re-adding the printer, and it can have different defaults — including Letter.

One more safe check: if you open Printer properties (not “Preferences” inside the app), is there a section showing Default paper size or Printing defaults? Just tell me what it currently says — no changes yet.
Customer
In Printer properties it says Letter as default. That’s probably the problem, right? I’m worried I’ll mess it up if I change it.
Technician avatar Technician
You found the key piece of information — and your caution is sensible.

I can’t tell you to “just change it and you’re done,” because sometimes the app overrides it, and sometimes the second printer entry is the real culprit.

The safest approach is to confirm which printer entry you’re actually printing to, and whether the document itself is Letter-sized. If the file is Letter, you may need to use a “fit to page / scale” option rather than forcing a paper size change.

If you tell me which printer name is selected in your print window (the exact one), we can decide what the lowest-risk adjustment would be.
Customer
It’s selecting the “Copy 1” printer most of the time. I didn’t even notice. That sounds like what changed after it was re-added.
Technician avatar Technician
That’s a very reasonable explanation, and it happens a lot after reinstalling printers.

One more “safe check first” idea: try selecting the other Brother entry (the one without “Copy 1”) and look at the paper size shown in the print window. Don’t print yet — just see whether it still shows Letter or switches to A4.
Customer
The other one shows A4 in the print window. So it’s probably just choosing the wrong printer entry. I feel relieved.
Technician avatar Technician
I’m glad you feel relieved — and you handled this calmly, which prevents accidental “fixes” that create new problems.

If you keep seeing Letter on certain PDFs, that may be the file’s own page size. In that case, the safest next step is to check the PDF’s page size and use a gentle scaling option instead of forcing a driver change.

If you want, tell me one example (PDF or Word) where it still misbehaves, and we can narrow whether it’s the document, the app, or the printer defaults.

Quick answer: the accepted fix

Accepted fix for My printer keeps printing Letter instead of A4 — what did I change?: confirm where the paper size is being chosen. First, check the paper size shown in the app’s print window (PDF viewer/Word) and make sure you are selecting the correct printer entry (avoid “Copy 1” duplicates if they have different defaults). Next, verify the printer tray guides match A4 and that the driver’s default paper size isn’t set to Letter. If only certain PDFs behave this way, treat it as a document-page-size mismatch and use safe “fit/scale” options rather than forcing resets or changing the printer’s panel settings.

Common reasons a printer switches from A4 to Letter without warning

Many printers have buttons that look harmless but can start a setup mode, clear network settings, or cancel a job you still need. That’s why people often hesitate to press anything — especially when the printer has blinking lights and no clear message.

In most cases, you can safely do basic checks first (paper tray, covers, obvious jams) and use simple controls like Cancel or Resume. The goal is to avoid accidental changes to Wi-Fi or “factory reset” options until you know what the warning light means.

What to check first when your printout is cut off or scaled wrong

If printing stopped suddenly, it’s often something small: a stuck print queue, the printer being set to Offline, or a paper/door sensor that didn’t latch properly. These are common after a power flicker, router restart, or Windows/macOS update.

A calm step-by-step approach keeps you from making it worse: confirm the printer has paper, confirm it’s powered on, confirm the computer sees it online, and only then move toward deeper troubleshooting.

Printer prints Letter instead of A4: safe checks before you change defaults

Start with low-risk checks and avoid resets until you know the cause.

Look for an obvious paper issue, confirm covers are fully closed, and check your computer’s print queue for “Offline” or stuck jobs. If you need to press a button, Cancel and Resume are usually safer than Wi-Fi setup or long-press combinations.

Disclaimer: This information is AI-generated and intended for general guidance only. For advice specific to your printer model and home/office setup, please consult a verified expert on Whizz-Tech before changing system settings.

Getting the right page size selected (without risky changes)

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We match you with a specialist who can guide you calmly through what’s safe to press and what to avoid, so you don’t accidentally trigger Wi-Fi setup or reset modes.

Fix the problem without extra stress

Get a simple checklist: check paper and covers, confirm the printer is online, clear stuck print jobs safely, and only then consider deeper troubleshooting if needed.

FAQ

Why did my printer start printing Letter instead of A4?

This often happens after a Windows update, reinstalling the printer, or switching to a different printer entry (like “Copy 1”). The default paper size may have returned to Letter in the driver or the app. It can also be triggered by a document that is actually Letter-sized.

Is this a printer problem or a settings problem?

Most of the time it’s a settings mismatch rather than hardware. The paper size can be set in the app, in the Windows print window, and in the printer’s driver defaults. Checking which place is “winning” is usually the safest first step.

Did this happen after an update or reinstall?

Yes, that’s very common. Updates or re-adding a printer can install a different driver profile with U.S.-style defaults (Letter). It can also create a second printer entry that uses different defaults.

Can this be checked safely at home without resetting anything?

Yes. You can safely check the paper size shown in the print window, confirm you’re selecting the correct printer entry, and look at the driver’s default paper size. Avoid factory resets or changing printer-panel settings until you know where the mismatch is coming from.

Sources

Filed under: Printer won’t print

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