How to Fix Outlook Signature Not Showing or Formatting Incorrectly

Applies to: Microsoft Outlook (Microsoft 365, Outlook 2021, New Outlook for Windows, Outlook on the Web), Windows 10, Windows 11
Article Type: Troubleshooting
Last Updated: 2026-06-17

Summary

This article covers what to do when your Outlook email signature does not appear on new messages or replies, loses its formatting (images missing, fonts wrong, layout broken), or stops attaching automatically after an Outlook update or profile change. These steps address the most common causes across Classic Outlook, New Outlook for Windows, and Outlook on the Web.

Prerequisites

• A Microsoft 365 email account with Outlook access.
• No admin rights required — all steps use standard user settings.

Instructions

1. Verify Your Signature Is Set as the Default

Outlook lets you create multiple signatures but only applies the one set as the default. If the default assignment was cleared — often after an update — no signature is attached automatically.

1. Open Outlook (Classic or New).
2. Go to File > Options > Mail > Signatures (Classic Outlook) or Settings (gear icon) > Mail > Compose and reply (New Outlook / Web).
3. In the Choose default signature section, check two drop-downs:
   • New messages: Select the signature you want on new emails.
   • Replies/forwards: Select the signature you want on replies and forwards. This is often set to (none) by mistake.
4. If your email account has multiple accounts configured, verify the correct account is selected in the E-mail account drop-down — each account has its own default signature setting.
5. Click Save or OK.
6. Send a test email to yourself to confirm the signature appears.

2. Check Your Message Format (Plain Text vs. HTML)

Signatures with formatting, logos, or images require HTML format. If Outlook is composing in plain text, all formatting is stripped.

1. Go to File > Options > Mail (Classic Outlook) or Settings > Mail > Compose and reply (New Outlook).
2. Look for the Compose messages in this format setting.
3. Ensure it is set to HTML (not Plain Text or Rich Text).
4. Click OK or Save.
5. If a specific email thread is stuck in plain text: open a reply to that email, click the Format Text tab (Classic) or the … menu (New Outlook), and switch the format to HTML for that message.

3. Fix Missing Signature Images

If your signature shows red X placeholders or blank boxes instead of images, Outlook cannot reach the image source.

1. Open Settings > Mail > Compose and reply and edit your signature.
2. Check how images were added:
   • Linked images (hosted on a website) break if the URL changes or the host goes down. Right-click the broken image area and check if the source URL is still valid.
   • Embedded images (pasted or inserted directly) are stored with the signature and are more reliable.
3. To fix: delete the broken image from the signature editor, then re-insert it:
   • Click the Insert image icon (picture icon) in the signature editor.
   • Browse to the image file on your computer and insert it.
4. Save the signature and send a test email to verify images display correctly.

4. Re-create the Signature in New Outlook or Outlook on the Web

If your signature worked in Classic Outlook but broke after switching to New Outlook, the signature may need to be re-created. Classic and New Outlook store signatures differently — Classic uses local files, while New Outlook syncs from the cloud.

1. Open New Outlook or Outlook on the Web (outlook.office.com).
2. Go to Settings (gear icon) > Mail > Compose and reply.
3. Scroll to the Email signature section.
4. If your old signature appears garbled, select all the text and delete it.
5. Re-create the signature using the built-in editor:
   • Type your name, title, and contact details.
   • Use the formatting toolbar to set fonts, sizes, and colours.
   • Insert your logo or image using the image icon.
6. Set it as the default for New messages and Replies/forwards.
7. Click Save and send a test email.

5. Clear the Signature Cache (Classic Outlook)

Classic Outlook stores signatures as local files. If these files become corrupted, the signature may display incorrectly or not at all.

1. Close Outlook completely.
2. Press Win + R to open the Run dialog.
3. Type %appdata%\Microsoft\Signatures and press Enter.
4. This opens the folder where Outlook stores your signature files. You will see files with .htm, .rtf, and .txt extensions for each signature.
5. Back up the folder by copying it to your Desktop.
6. Delete all files in the Signatures folder.
7. Reopen Outlook and go to File > Options > Mail > Signatures.
8. Re-create your signature from scratch and set the defaults.
9. Send a test email to confirm the signature appears correctly.

6. Verify Organisational Signature Policies

Some organisations use server-side signature policies (via Exchange transport rules or third-party tools like Exclaimer or CodeTwo) that override your personal Outlook signature settings.

1. Send a test email to an external address (e.g., your personal email) and check what signature appears.
2. If the received email shows a different signature than what you configured — or shows a corporate template — your organisation applies a server-side signature.
3. In this case, your locally configured signature may be intentionally overridden. Changes need to be requested through your IT department.
4. If both a personal and corporate signature appear (duplicated), ask IT to confirm the corporate signature is applied to every outbound message. Once they confirm it, delete your local signature so recipients stop seeing both.

7. When to Contact IT

Attach the test email from Step 6 to your ticket and say what the signature looks like as you compose it versus what actually arrived. That single comparison tells IT whether the problem sits in your Outlook profile or in a server-side rule, and saves a round of back-and-forth.

Contact your IT helpdesk if:

• Your organisation uses a centrally managed signature tool and you need to update your details (title, phone number, department).
• You have followed all steps above and the signature still does not appear on emails received by others.
• Your signature works in Outlook but is stripped when the recipient opens the email — this may indicate a transport rule or email gateway issue on the server side.
• Multiple colleagues are experiencing the same signature issue — this suggests a policy or server-side change.

Troubleshooting

INFO

Signatures in Classic Outlook and New Outlook are stored in different locations. A signature created in Classic Outlook may not automatically appear in New Outlook. If you recently switched versions, re-create the signature in the new version (Step 4).

Symptom / Error	Potential Cause	Solution
Signature appears on new messages but not replies	Default not set for replies/forwards	Set the reply/forward default in signature settings (Step 1).
Signature loses all formatting	Message composed in plain text	Switch compose format to HTML (Step 2).
Images show as red X or blank boxes	Linked image URL broken or blocked	Re-insert images as embedded files (Step 3).
Signature works in Classic but not New Outlook	Different storage locations	Re-create signature in New Outlook (Step 4).
Signature disappeared after update	Signature cache corrupted	Clear signature cache and re-create (Step 5).
Corporate signature overrides personal one	Server-side signature policy active	Ask IT to update your details in the central signature tool, and give them the exact name, title, and phone number you need (Step 6).
Signature font changes when recipient opens email	Font not web-safe	Use standard fonts (Arial, Calibri, Verdana) that display consistently across email clients.

Related Articles

• How to Create an Email Signature in Outlook
• How to Customize the New Outlook for Windows
• Understanding Outlook Versions — Classic vs. New vs. Web
• How to Send, Reply, and Forward Email in Outlook
• How to Fix Outlook Not Responding or Freezing
• How to Fix Outlook Emails Not Syncing

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