Office for Mac Issues

Fix Outlook for Mac Replies Displaying Mixed Font Sizes

Maira Mehtab Sep 28, 2026 869 views

Question details

Users are experiencing an issue where text in Outlook email replies displays in inconsistent or mixed font sizes despite correct default font configurations.

How to Fix Outlook for Mac Replies Displaying Mixed Font Sizes

Product: Microsoft Outlook for Mac
Device & OS: macOS
Scenario: Replying to emails received via an IMAP mail server or formatted in HTML using the Outlook desktop client.
Observed behavior: The sent message uses a consistent font, but some replies display randomly larger text that overrides the user's default font settings.

Before you start

Before troubleshooting, verify your current macOS and Outlook versions to ensure they are fully up to date, and test if the same formatting issue occurs when using Outlook on the web.

Solution 1Recommended

Clear Direct Formatting and Standardize Message Format

Resolve formatting conflicts carried over from the original message by clearing direct formatting and ensuring a consistent HTML or Plain Text format.

Often, email replies inherit hidden CSS or HTML formatting from the original sender's message. Clearing this direct formatting can reset the text to your default settings.

Select All Text

Click inside your reply window and press Command + A on your keyboard to select all the text in the email draft.

Clear Formatting

Navigate to the Message tab on the ribbon and click the 'Clear Formatting' button (usually an 'A' with an eraser icon) to strip away hidden styles.

Set Consistent Format

Go to the 'Format' menu at the top of the screen and ensure either 'HTML' or 'Plain Text' is consistently selected.

Reapply Default Font

Manually re-select your desired font and font size from the ribbon to ensure the entire message is uniform before sending.

Clear Direct Formatting and Standardize Message Format

Tip: Using 'Plain Text' is the most reliable way to strip all conflicting size attributes, though it will also remove images and hyperlinks.

Solution 2

Verify Default Fonts and Update Outlook

Ensure that software bugs causing rendering issues are patched by installing the latest updates and re-confirming your font preferences.

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Frequently Asked Questions

Why does my font size change randomly when replying to an email in Outlook for Mac?

This usually happens because Outlook carries over hidden HTML or CSS formatting from the original sender's message. Conflicts between IMAP conversion and Outlook's rendering engine can also cause font sizes to appear randomly larger.

How do I set a default font for email replies in Outlook for Mac?

Go to 'Outlook' > 'Settings' (or Preferences) in the top menu bar, then click 'Fonts'. Under the 'Reply or forward' section, click the 'Font' button to choose your preferred typeface and size, then click 'OK' to save.

Does switching to Plain Text fix mixed font sizes in emails?

Yes. Switching your reply format to Plain Text strips all HTML formatting, ensuring that the text displays in a single, consistent default font without any imported size variations from the original sender.

What should I do if updating Outlook doesn't fix the formatting issue?

If the issue persists across updates, test your email account using Outlook on the web or another mail client like Apple Mail. If the email formats correctly on the web, the problem is specific to the Outlook for Mac desktop client, and you should report the bug to Microsoft Support.

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