Win/11, Office 365 Word, Having issues with fonts/font sizing randomly changing

Tom Benson 40 Reputation points
2026-11-03T23:05:01.72+00:00

I have a word template that has been working for years and about 2-3 weeks ago it suddenly stopped working correctly.

The template is a simple one that just centers all text on a page with 'bold' text option selected. For years, I have been able to type the following into this document... #, then press the space bar, then any number or groups of numbers, for example: # 12345-A. This line remained centered as per template and there was no font/size changes. It always worked perfectly. Results were the same if you type #, space bar and the any characters you want. for example... '#, space bar and 'the cat is yellow'.

The last 2-3 weeks when I type the line... #, then space bar and then any number(s) the # sign is dropped, the remaining characters after the space bar is pressed are left justified and the font type changes from Calibri (Body) to Calibri Light (Headings) and the font size increases from 14 to 16 and is no longer 'bold'. The same results happened and the typed #, then space bar, 'the cat is yellow' becomes left justified as... 'the cat is yellow' and the # is dropped.

I have tried the above using the 'normal.dot' word template and results are the same without using centering text option and I get the same results as per above.

However, in both templates if I type '#12345-A' or '#the cat is yellow' without pressing the space bar after the #, the text shows perfectly just as it was typed. No left justification on centered template, no font change, no font size change! I'm guessing the error has something to do with the # being followed by a space then any additional text.

I have spent hours (3 different call days) with Microsoft with no solution and they referred me to this users group, today's earlier ticket number (I can supply it) is open and they specifically told me it could be referenced by this group. Fingers crossed. I have also reversed Office 365 updates back to August 2026 (same erroneous results) and re-installed Office 365 three time over the last 3 weeks.

Any help or direction is certainly appreciated. Please advise if you need more details.

Microsoft 365 and Office | Word | For home | Windows
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Answer accepted by question author
Stefan Blom 357.2K Reputation points MVP Volunteer Moderator
2026-11-03T23:45:19.5966667+00:00

The AI bot is right. You have encountered a new "feature" in Word which applies a heading style as you type one or more hashtags. Clear the markdown option at File > Options > Proofing > AutoCorrect Options > AutoFormat As You Type.

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Answer accepted by question author

AI answer

2026-11-03T23:06:04.8066667+00:00

Disable Word’s Markdown for Heading, Bold, Italic and Strikethrough option, which interprets # at the beginning of a paragraph as a heading marker rather than literal text.

Disable the Markdown shortcut

  1. Open Word.
  2. Select File → Options.
  3. Select Proofing.
  4. Select AutoCorrect Options.
  5. Open the AutoFormat As You Type tab.
  6. Clear Markdown for Heading, Bold, Italic and Strikethrough.
  7. Select OK, and then OK again.
  8. In a new paragraph, test:
       # 12345-A
    
    The # should remain visible, and the paragraph should retain its existing centering, bold setting, font, and size.

This exact option resolved a matching Word for Microsoft 365 on Windows case in which Word unexpectedly switched text from Normal formatting to a Heading style. The recommended path was Proofing → AutoCorrect Options → AutoFormat As You Type, followed by clearing the Markdown option.^1^

The behavior also matches Markdown heading syntax: a # followed by a space denotes a level-one heading. That accounts for Word consuming the marker and applying heading formatting, while #12345-A remains unchanged because there is no space.

Reinstalling Office or rolling back updates would not necessarily change this preference, so those already-tried actions do not need to be repeated.

Repair paragraphs already converted

For a paragraph that Word has already changed:

  1. Click inside the affected paragraph.
  2. Press Ctrl+Shift+N to apply the Normal style.
  3. Press Ctrl+E to restore centered alignment.
  4. Reapply bold and the required font size if necessary.

Word documents Ctrl+Shift+N for Normal style and Ctrl+E for centering.^2^

If the Markdown option is not shown

Reproduce the problem once and immediately open the Undo drop-down on Word’s Quick Access Toolbar. Note the action Word says it will undo. In another spacebar-triggered Heading 1 case, checking that entry was recommended to distinguish an automatic formatting action from a formatted AutoCorrect replacement.^3^

If it identifies an AutoCorrect replacement rather than Markdown or heading formatting, inspect File → Options → Proofing → AutoCorrect Options → AutoCorrect for a formatted entry triggered by #. Do not delete unrelated entries.


References

  1. Word automatically recently switching from Normal mode to Heading mode, mid-paragraph, every document - Microsoft Q&A
  2. [Windows](https://support.microsoft.com/accessibility/word/keyboard-shortcuts-in-word#edit-text-and-graphics)
  3. Hitting space bar causes paragraph to change style
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