Microsoft Outlook remains the dominant email client for businesses worldwide, yet many users struggle with invisible formatting issues caused by non-printing characters. These hidden elements - including paragraph marks, tabs, and spacing indicators - can dramatically affect email appearance across different clients and devices.

What Are Non-Printing Characters?

Non-printing characters (also called formatting marks) are special codes that control document layout without being visible in the final output. In Outlook, these include:

  • Paragraph marks (¶): Indicate line/paragraph breaks
  • Tab arrows (→): Show tab key presses
  • Spaces (·): Represent spacebar presses
  • Hidden text: Formatted as invisible but still present
  • Object anchors: Show image/text box positioning

Why Non-Printing Characters Matter in Outlook

These hidden elements cause three major problems:

  1. Formatting inconsistencies: What looks perfect in Outlook may appear broken in Gmail or Apple Mail
  2. File size bloat: Excessive formatting marks increase email size
  3. Accessibility issues: Screen readers may interpret hidden characters unexpectedly

How to View Non-Printing Characters

In Classic Outlook (2019 and earlier)

  1. Open a new email
  2. Navigate to the "Format Text" tab
  3. Click the paragraph mark icon (¶) in the Paragraph group

In New Outlook (Web/365)

Microsoft removed the direct toggle, but workarounds exist:
1. Paste content into Word Online first
2. Use Ctrl+ (Windows) or Cmd+ (Mac) to toggle marks
3. Install the Office Tooltip add-in for persistent viewing

Common Formatting Issues and Fixes

Problem 1: Uneven Spacing

Cause: Mixed use of spaces and tabs
Solution:
- Use consistent paragraph spacing (Format > Paragraph)
- Replace tabs with proper indentation

Problem 2: Broken Line Breaks

Cause: Manual line breaks vs paragraph breaks
Solution:
- Use Shift+Enter for line breaks within paragraphs
- Use Enter only for true paragraph separation

Problem 3: Hidden Text Corruption

Cause: Invisible formatting from other apps
Solution:
1. Paste as plain text (Ctrl+Shift+V)
2. Reapply formatting in Outlook

Advanced Workarounds for Power Users

Registry Hack for Persistent View (Windows)

  1. Open Regedit
  2. Navigate to HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Options\Mail
  3. Create DWORD "ShowMarkup" with value 1

Using Word as an Editor

  1. Set Word as default email editor (File > Options > Mail)
  2. Access full formatting mark controls from Word's ribbon

Clean HTML Approach

For critical emails:
1. Compose in HTML editor like VS Code
2. Use semantic HTML tags
3. Paste final code into Outlook's HTML source view

Best Practices for Professional Emails

  • Standardize fonts: Use web-safe fonts like Arial or Georgia
  • Limit formatting: Bold/italic only for emphasis
  • Test across clients: Check in Gmail, Apple Mail, and mobile
  • Use tables for layout: More reliable than floating elements
  • Keep CSS inline: External styles often break

The Future of Outlook Formatting

Microsoft's "New Outlook" promises improved rendering consistency through:

  • Better HTML5 support
  • Shared rendering engine across platforms
  • AI-assisted formatting cleanup (coming 2024)

Until then, mastering non-printing characters remains essential for anyone creating business-critical emails in Outlook.