How to Prevent Outlook Signatures from Appearing as Attachments

When you compose emails with ContactMonkey, your Outlook signature may appear as unwanted attachments at the bottom of messages. This happens because:

• Outlook automatically inserts signatures containing images (logos, social media icons) as inline attachments
• These inline attachments remain attached to the draft even after you clear the email body
• Email clients like Apple Mail on iPhone and iPad display these inline images as visible "attachments"
• This increases message size and may trigger email throttling or rate limits

Reference: Microsoft Learn - Managing Inline Attachments

The Solution

Don't use Outlook's auto-insert signature feature when composing with ContactMonkey. Instead, add your signature content directly to your ContactMonkey template footer.

This approach:

• Eliminates hidden inline attachments
• Reduces message size
• Prevents attachment display issues
• Improves email deliverability

Step 1: Create a Blank Signature in Outlook

1. Open Outlook
2. Create a new signature named "CM – Blank"
3. Leave the signature completely empty, or add only plain text (like your name)
4. Save the signature

Need help creating signatures? See Microsoft's signature guide

Step 2: Select the Blank Signature When Using ContactMonkey

When composing emails with ContactMonkey:

• Manually select "CM – Blank" from your signature dropdown
• OR set it as your default signature for new messages in Outlook settings

When composing regular emails:

• Switch back to your regular signature

Step 3: Add Signature Content to Your Template Footer

1. Open your email in the Email Builder
2. Add branding, legal disclaimers, and contact information to the template footer
3. For logos and images:
   • Recommended: Use hosted images (linked URLs) instead of embedded images
   • This prevents attachment issues entirely

Note: Some recipients may need to click "Download images" to view linked images. This is normal email security behavior.

Why Apple Mail Shows These Attachments

Apple Mail (especially on iPhone and iPad) displays inline images as attachments even when other email clients don't. This is Apple Mail's default behavior and cannot be overridden from Outlook's side.

Using the "CM – Blank" signature with template footers is the most reliable workaround across all email clients.

Reference: CodeTwo - Understanding Inline Attachments

Why ContactMonkey Can't Remove These Attachments

Outlook's Office.js API allows Add-ins to remove regular file attachments, but not inline signature attachments. While Microsoft's guidance suggests removing body references, Outlook's handling of inline images is inconsistent across different email clients, making automatic removal unreliable.

Preventing the signature from being inserted in the first place is the most dependable solution.

Reference: Microsoft Learn - Office Add-ins API