Line Spacing Automatically Changing

Hi @Zornes, Madelynne,

Good day, and thank you for taking the time to provide such a detailed description of the issue.

Based on my research, the behavior you are experiencing appears to be related to how Outlook’s message editor handles formatting during email composition. In some cases, the editor may automatically reapply paragraph or list formatting as content is added or modified, particularly when working with line spacing, bullet points, or text styling such as bold or italics. This can result in spacing changes that do not always reflect the formatting option that was selected.

To help better understand and narrow down the cause, I would recommend checking and clarifying the following with Outlook on the web, as it uses a consistent, browser-based editor:

1/ Test with a new blank message

Create a brand-new email (rather than replying to or forwarding an existing message). Enter a few lines of text and apply single spacing, then add bullet points and basic formatting such as bold or italics. Please observe whether the line spacing remains consistent while typing.

If the spacing remains consistent, this suggests the behavior may be related to formatting inherited from replies, forwards, or pre-existing content.

2/ Verify the message format

Ensure that the email is being composed in HTML format, as message format can affect how spacing and paragraph styles are applied during composition.

To check this in Outlook on the web:

• Create a new email message.
• In the compose window, select the Options (⋯) menu.
• If Plain text is selected, switch it off to return the message to HTML format.
• Once the message is confirmed to be in HTML format, enter a few lines of text and apply line spacing, bullet points, and basic formatting to check whether the spacing behaves consistently.

3/ Remove automatic or pre-inserted content

• Start a brand-new message (not reply/forward).
• Temporarily remove the signature from that message (or choose “no signature” if prompted).
• Type a few lines, apply bullets, then bold/italic, and see if spacing still “jumps.”

If the issue no longer occurs when the signature is removed, this would indicate that the behavior is likely related to the signature’s formatting. In this case, it is recommended to review and simplify the signature structure, particularly if it contains tables, multiple font definitions, or HTML content copied from external sources.

4/ Try a different browser or private browsing session

Access Outlook on the web using an alternative browser or an InPrivate/Incognito browsing session to help determine whether browser cache, extensions, or local browser settings may be affecting the message editor.

5/ Contact Microsoft Support

If the issue persists after applying these steps, the best next step would be to have your IT administrator open a support ticket with Microsoft via the admin center. A technical support engineer can then initiate a remote session, review backend settings, and run diagnostics. If needed, they can escalate the case to specialized engineering teams who are well-equipped to perform advanced troubleshooting and provide targeted solutions.

As moderators, our primary goal is to provide helpful guidance and support through general troubleshooting steps. While we don’t have access to internal systems or administrative tools required to resolve account-specific or backend issues, we truly appreciate your understanding of these limitations. We genuinely hope the information we share helps point you in the right direction, and we're always here to assist as much as we can within our scope.

For guidance on how to request support in the admin center, please share this link with your IT admin: Get support - Microsoft 365 admin. 

I hope this information is useful. Thank you for taking the time to raise this question. If you need any further clarification or assistance, please feel free to leave a comment under this post.

If you find my post useful, kindly consider upvoting it. Doing so can assist others in the community who may have similar questions in finding solutions more quickly.

Thank you for your contributions to the forum.

Note: Please follow the steps in this documentation to enable e-mail notifications if you want to receive the related email notification for this thread.