Spellcheck, in Rich Text, on a mac

[para-CAD]

It's never worked for me since 2015.  Is it a mac setting?

 

 

[Eric_S]

Mac spell check does not flag words written in all caps as incorrect. I believe this is general behavior across multiple Mac applications.

[rwdozier]

FWIW - AI says...

 

You spotted a real and very common behavior — and yes, both Windows and macOS (and most browsers and apps) often do NOT spell-check words typed in ALL CAPS by default.

And your screenshot clearly shows it:

• BECASUE (all caps) → no red underline

• becasue (lowercase) → red underline

Let me explain why this happens and what you can do about it.

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Why all-caps words are often NOT spell-checked

Most operating systems and applications intentionally skip spell-checking all-caps words because historically:

1. All-caps are usually treated as acronyms

Programs assume that text in ALL CAPS might be things like:

• NASA

• CPU

• HTML

• USA

• ASAP

To avoid false warnings, developers traditionally disable spell-check for all-caps strings.

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2. Many documents use all-caps for headings or emphasis

If spell-check underlined every title like:

IMPORTANT INFORMATION TERMS AND CONDITIONS

…it would annoy users and clutter the screen, especially in older word processors.

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3. Legacy behavior from early word processors

This tradition dates back to:

• WordPerfect

• Microsoft Word 95–2003

• Early macOS text systems

Those programs defaulted to treating ALL CAPS as “don’t check” text, and the behavior has stayed for consistency.

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Apps & systems known to skip spell-check on ALL CAPS

• Microsoft Word (unless you disable the setting)

• Windows spell-checker (system-wide)

• Chrome/Edge browser

• macOS system spell-checker (Safari, Notes, etc.)

• Most email clients

This is normal and expected behavior.

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How to enable spell-check for ALL CAPS (if you want it)

Microsoft Word

1. Go to File → Options

2. Choose Proofing

3. Uncheck:
   ✔️ “Ignore words in UPPERCASE”

Word will then underline misspellings in all caps.

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macOS (system-wide)

macOS provides no built-in toggle, and many apps do not check all-caps text.
Some apps (like Pages) do check all caps, but browsers and text fields usually do not.

No universal fix.

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Web browsers (Chrome, Edge, Firefox)

There is no settings toggle to force spell-checking on ALL CAPS in the browser text fields. It depends on the underlying OS dictionary.

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Conclusion

Your screenshot is behaving exactly as designed.
Spell checkers skipping ALL CAPS is a longstanding convention meant to avoid flagging acronyms, technical terms, and headings.

If you want it checked, Microsoft Word lets you enable the option — but browsers and many system text inputs still won't.

[para-CAD]

YESSSS!!!

 

Thank you both for reminding me of the all-caps thing.  

All my plan text is ALL CAPS Arial.

 

I guess I could start doing sentence case and then select all and press the Aa button.

 

Thanks again, gents.

[tundra_dweller]

The Anycase app is a fantastic tool for changing text case quickly after the fact. https://anycaseapp.com/ 

Thanks to @Alaskan_Son for bringing attention to this app. I don't think it does spellcheck though.