Why your Outlook signature link is blue and underlined

Outlook can make a signature link blue and underlined for two reasons. The first is automatic: Outlook turns a web address you type into a link, and a setting turns that off. The second is a link you colored yourself, which Outlook for Mac can switch back to blue in new messages. Microsoft documents the first case. For the second, I found only community answers.

How do I stop Outlook from making links?

Microsoft's page covers Outlook for Microsoft 365 and Outlook 2016 through 2024, and it gives the File menu path. It does not describe Outlook for Mac.

1. Click File > Options > Mail.
2. Under Compose messages, click Editor Options.
3. Click AutoCorrect Options, then open the AutoFormat As You Type tab.
4. Clear the Internet and network paths with hyperlinks check box.
5. Close the dialogs.

Microsoft says Outlook then will not create hyperlinks automatically. The page does not say whether links already in your signature change, so open the signature and check it. To test the change quickly, type a web address into a new draft. If it stays plain text, the setting is working in the version you use.

How do I remove a link and keep the text?

Right-click the link and choose Remove Hyperlink. The text stays and only the link goes. To remove the link and its text, select it and press Delete. Microsoft's page on removing hyperlinks gives both steps.

Why does my link turn blue again in Outlook for Mac?

Microsoft's documentation does not cover this. The clearest report is a Microsoft Q&A thread from 9 September 2025 about New Outlook for Mac. The author colored one signature link black and one green. After closing the signature editor, both links showed blue in every new message, even after editing them back. The four replies are community answers, not Microsoft documentation. They suggest:

• Set the link colors in the signature editor, not in the compose window. Then quit Outlook completely and reopen it. One reply calls this only a temporary workaround.
• Turn off Optional Connected Experiences in the privacy settings, then choose Clear Application Data from the Help menu and restart Outlook.
• For an Exchange account, compose signature emails in Outlook on the web. One reply says link colors hold up there.

Another user in the same thread said that rebuilding the signature from scratch did not help, so do not count on that step.

An older Microsoft Q&A reply, from 2017 about legacy Outlook for Mac, says a link is underlined only when Outlook recognizes the text as a hyperlink. It suggests typing the address without http:// or https://. That was for the old app, so test it before you rely on it.

What about email addresses and phone numbers?

The AutoFormat page names web addresses only. A Q&A thread titled "Email in Signature hyperlinks after sending" describes an address that became a link after sending, and a reply points to the same checkbox. That is a community answer, so send yourself a test message before you rely on it. I found no Microsoft documentation for phone numbers, so this guide does not cover them.

How Sendoff handles this

Sendoff writes phone, email and website entries as tel:, mailto: and web links. Each one carries an explicit text color and text-decoration:none in its inline style, and Copy HTML gives you the same markup. Outlook can still restyle a link, as the Mac reports show, so send a test message to yourself and check the copy in your Sent folder. The free generator is at /email-signature-generator.

Sources

• Microsoft Support, "Stop text from turning into a hyperlink": https://support.microsoft.com/en-us/office/stop-text-from-turning-into-a-hyperlink-f361cb96-02e4-40bb-b39c-0ef5e2faac90
• Microsoft Support, "Remove or turn off hyperlinks": https://support.microsoft.com/en-us/office/remove-or-turn-off-hyperlinks-027b4e8c-38f8-432c-b57f-6c8b67ebe3b0
• Microsoft Q&A, "The hyperlink colors in my signature are reverting to blue - how can I fix that?" (community replies, 9 September 2025): https://learn.microsoft.com/en-us/answers/questions/5550091/the-hyperlink-colors-in-my-signature-are-reverting
• Microsoft Q&A, "HTML email signatures (link underline and image spacing)" (2017, legacy Outlook for Mac): https://learn.microsoft.com/en-us/answers/questions/4532572/html-email-signatures-(link-underline-and-image-sp
• Microsoft Q&A, "Email in Signature hyperlinks after sending" (community reply): https://learn.microsoft.com/en-us/answers/questions/4651517/email-in-signature-hyperlinks-after-sending