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Microsoft Word 📅 2026-02-02

How to Fix Word Highlighting and Underlining Not Showing

🚨 Symptoms & Diagnosis

When meticulously formatting documents in Microsoft Word, it can be perplexing when applied highlights or underlines fail to render visually. This display anomaly can disrupt document review, collaboration, and overall productivity.

  • Highlight and underline buttons indicate active but no visual effect
  • Text underline not visible in Dark Theme
  • Select highlight doesn't work past two lines
  • Word won't underline blank spaces
  • Can't highlight or select words on document

Root Cause: These rendering discrepancies often arise from corrupted formatting caches, conflicts with the default Normal.dotm template, conflicting display options, or theme-specific color clashes (especially in Dark Mode). Such issues can prevent the Word Formatting Engine from correctly processing and displaying visual markup.

🛠️ Solutions

Reapply Formatting with Find and Replace

Immediate Mitigation: Quick Fix: Find and Replace Formatting

This method efficiently restores hidden highlights and underlines by batch reapplication, effectively refreshing their display properties across the document.

  1. Press Ctrl+H to invoke the Find and Replace dialog.
  2. Click the More >> button to expand the dialog options.
  3. Place your cursor within the Find what: field.
  4. Click Format, then select Highlight from the dropdown. This configures the Find what field to target existing highlighted text.
  5. Ensure the Replace with: field is clear of any formatting (click No Formatting if necessary).
  6. Place your cursor in the Replace with: field.
  7. Click Format, then select Highlight from the dropdown. This instructs Word to replace existing highlights with newly applied highlight formatting.
  8. Click Replace All.
  9. Repeat steps 3-8, this time selecting Underline (and choosing the desired underline style if prompted) for both the Find what and Replace with fields to address underlining issues.
Ctrl+H (Find & Replace dialog)

Adjust Theme and Underline Color

Best Practice Fix: Theme/Underline Color Adjustment

This solution specifically targets visibility issues in themes like Dark Mode by allowing you to explicitly set a contrasting underline color.

  1. Navigate to the Home Ribbon tab.
  2. In the Font group, locate and click the dropdown arrow adjacent to the Underline button (typically an 'U' with a line beneath).
  3. Choose a specific underline style, such as Thick Underline, or select More Underlines... to access additional configuration options.
  4. From the Underline Color menu, select a color that provides sufficient contrast and is clearly visible against your current document theme (e.g., Green, Bright Blue).
  5. Validate the change by applying an underline in a new document to confirm its visual presence.
Home Ribbon > Underline > More Underline Styles

Reset Display Settings and Template

Best Practice Fix: Reset Display Settings & Template

This approach resolves conflicts stemming from specific display options and addresses potential corruption within the default Word template (Normal.dotm), which can interfere with standard formatting display.

  1. Access the Word Options dialog via File > Options.
  2. From the left-hand navigation pane, select Advanced.
  3. Scroll down to the Show document content section.
  4. Verify that Show highlighter marks is checked. If unchecked, highlights will intentionally not appear.
  5. Click OK to commit the display setting changes.
  6. Completely close all instances of Microsoft Word.
  7. Open the Run dialog by pressing the Win + R keys.
  8. Type %AppData%\Microsoft\Templates and press Enter to open the Templates folder.
  9. Locate the Normal.dotm file.
  10. Rename Normal.dotm to Normal_old.dotm. Word will automatically generate a new, pristine Normal.dotm file upon its next launch.
# Path to Normal.dotm
%AppData%\Microsoft\Templates\Normal.dotm

Reset Office Registry Settings

Data Loss Warning

Incorrect modifications to the Windows Registry can lead to severe system instability or data loss. It is imperative to back up your registry before proceeding or to exercise extreme caution. This step involves resetting core Word configuration settings and should be considered only when all other solutions have proven ineffective.

Best Practice Fix: Permanent Fix: Registry Reset

This method provides a comprehensive resolution by clearing potentially corrupted Office-wide settings, forcing Word to rebuild its configuration.

  1. Ensure all Microsoft Word applications are closed.
  2. Open the Run dialog by pressing Win + R.
  3. Type regedit and press Enter to launch the Registry Editor.
  4. Navigate through the registry tree to HKEY_CURRENT_USER\Software\Microsoft\Office.
  5. Right-click on the Office key in the left pane and select Rename.
  6. Rename the key to Office_old. This action will compel Word to reconstruct its registry settings the next time it starts.
  7. Close the Registry Editor and restart Microsoft Word.
# Relevant Registry Path (renaming the parent 'Office' key applies broadly)
HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\word\options

🧩 Technical Context (Visualized)

Microsoft Word's core functionality relies on a sophisticated Formatting Engine and a dedicated Display Rendering subsystem. When a user applies formatting like highlighting or underlining, the Formatting Engine processes these instructions based on current styles and themes. The Display Rendering subsystem then interprets this data to visually present the markup within the Rich Text Editor. Discrepancies often occur when elements such as a corrupted Normal.dotm template, incompatible theme settings (e.g., a dark theme obscuring a dark underline), or erroneous registry entries interfere with this rendering pipeline, resulting in applied formatting that remains invisible.

graph TD
    A[User Applies Highlight/Underline] --> B{Word Formatting Engine};
    B --> C{Display Rendering Subsystem};
    C --> D[Rich Text Editor Display];

    subgraph Problem Flow
        C --x E[Corrupted Normal.dotm / Cache]
        C --x F[Dark Theme Color Conflict]
        C --x G[Registry Setting Blockage]
        C --x H[Conflicting Display Option]
    end

    E --> I[No Visual Effect];
    F --> I;
    G --> I;
    H --> I;

    D -- "Success" --> J[Formatting Visible];

✅ Verification

Upon applying any of the described solutions, validate the fix by performing the following steps to confirm proper rendering:

  1. Initiate a new blank document in Microsoft Word.
  2. Input a few lines of sample text.
  3. Select a segment of the text and apply an underline using the Ctrl + U shortcut.
  4. Select a different portion of text and apply highlighting via the Home Ribbon tab > Text Highlight Color dropdown.
  5. Visually confirm that both the underline and highlight are displayed correctly in the Print Layout view.
  6. For a comprehensive check, navigate to File > Options > Advanced > Show document content and ensure that the Show highlighter marks setting is appropriately checked.

📦 Prerequisites

To effectively troubleshoot and resolve these issues, your environment should ideally include Microsoft Word 365 (Build 16.0 or newer) operating on Windows 11 or Windows 10. Administrator privileges are necessary for any operations involving the Registry Editor. Additionally, testing Word in Safe Mode (winword /safe via Run dialog) can be a valuable preliminary step to isolate potential conflicts with add-ins.