Why Cant I Highlight In Outlook

The missing highlight tool in Outlook is usually a sign you’re using the Reading Pane instead of opening the message. If you’ve ever wondered “why cant i highlight in outlook,” you’re not alone—it’s one of the most common frustrations for email users. The highlight feature, which lets you mark text with a yellow background, is incredibly useful for flagging important info, but it often seems to vanish when you need it most. In this guide, I’ll show you exactly why this happens and how to fix it, step by step.

Let’s be honest: Outlook can be a bit quirky. You might click around, search for the highlight button, and find it’s just not there. That’s not a bug—it’s a design choice. The Reading Pane, which shows a preview of your email without fully opening it, doesn’t support editing tools like highlighting. You need to open the message in its own window to see the highlight option. Once you know this, the solution is simple, but there are other reasons too, like using the wrong version or having a corrupted file. I’ll cover all of that.

In this article, I’ll walk you through the main causes, from the Reading Pane issue to settings problems, and give you clear fixes. You’ll also learn how to highlight in different Outlook versions, including web and mobile. By the end, you’ll never have to ask “why cant i highlight in outlook” again. Let’s dive right in.

The exact phrase “Why Cant I Highlight In Outlook” points to a core issue: the feature is hidden or disabled. Most users hit this wall because they’re viewing emails in the Reading Pane, which is designed for quick scanning, not editing. When you open the message separately, the highlight tool appears in the Format Text tab. But if it’s still missing, other factors could be at play, like your Outlook version or a corrupt add-in.

I’ve seen people spend hours troubleshooting, only to realize they just needed to double-click the email. It’s that simple. But let’s not assume—there are deeper causes too. For example, if you’re using Outlook on the web, the highlight feature might not be available at all, or it could be buried in a menu. I’ll break down every scenario so you can pinpoint your problem fast.

Main Causes For Missing Highlight In Outlook

Here are the most common reasons why the highlight tool is MIA. I’ve listed them in order of likeliness, so start with the first one.

Reading Pane active: You’re previewing the email instead of opening it. The highlight button only shows up in the full message window.
Wrong email format: Plain text emails don’t support highlighting. You need HTML or Rich Text format.
Outlook version: Some older versions or the web app may lack the feature entirely.
Disabled add-ins: A third-party add-in could be blocking the highlight tool.
Corrupt profile: Your Outlook profile might be damaged, causing missing features.

Each of these has a straightforward fix. I’ll explain them in detail below, starting with the most common culprit: the Reading Pane.

Fix 1: Open The Email In A Separate Window

This is the number one solution. If you’re viewing an email in the Reading Pane (the preview area on the right or bottom of your screen), you won’t see the highlight button. Here’s how to fix it:

Double-click the email in your inbox to open it in a new window.
Go to the Format Text tab at the top of the ribbon.
Look for the Text Highlight Color button (it looks like a yellow highlighter pen).
Select your text, then click the button to highlight it.

If you prefer to keep the Reading Pane open, you can still highlight by using a workaround: copy the text to Word, highlight it there, then paste it back. But opening the email is faster and cleaner. I always tell people to make it a habit—double-click any email you want to edit.

Fix 2: Check The Email Format

Outlook supports three message formats: HTML, Rich Text, and Plain Text. Highlighting only works in HTML and Rich Text. If the email is in Plain Text, the highlight button will be grayed out or missing. Here’s how to check and change it:

Open the email in a separate window.
Click Format Text in the ribbon.
Look at the Format group. It should say “HTML” or “Rich Text.” If it says “Plain Text,” click it and switch to HTML.
Now try highlighting again.

Note that you can’t change the format of an email you received—only ones you’re composing. For incoming emails, the sender’s format is fixed. If it’s plain text, you’re out of luck unless you copy the text to a new message. This is a common oversight, so double-check it before moving on.

Fix 3: Update Or Switch Outlook Version

If you’re using an older version of Outlook (like 2010 or 2013), the highlight feature might be limited or buggy. Microsoft has improved it over time. Also, Outlook on the web (OWA) sometimes hides the highlight tool in a menu. Here’s what to do:

Desktop version: Go to File > Office Account > Update Options > Update Now. Install any pending updates.
Web version: Open the email, click the three dots (More actions) in the toolbar, then look for “Highlight” under the Format or Edit menu. It’s not always visible by default.
Mobile app: The Outlook mobile app doesn’t have a highlight feature at all. You’ll need to use the desktop or web version for that.

I’ve noticed that the web version is particularly tricky—sometimes the highlight button only appears after you select text. So try selecting a word first, then check the toolbar.

Fix 4: Disable Problematic Add-Ins

Third-party add-ins can interfere with Outlook’s built-in tools. If you’ve installed add-ins for grammar checkers, CRM tools, or email tracking, they might be blocking the highlight feature. Here’s how to check:

Open Outlook and go to File > Options > Add-ins.
At the bottom, next to “Manage,” select COM Add-ins and click Go.
Uncheck all add-ins to disable them temporarily.
Restart Outlook and try highlighting again.
If it works, re-enable add-ins one by one to find the culprit.

This fix is less common but worth trying if the other steps fail. I’ve seen a popular grammar add-in cause this exact issue, so don’t skip it.

Fix 5: Repair Your Outlook Profile

A corrupt profile can cause all sorts of weird behavior, including missing buttons. You can repair it without losing your emails. Here’s the process:

Close Outlook.
Open Control Panel and search for “Mail.”
Click Show Profiles.
Select your profile and click Properties.
Click Repair and follow the prompts.
Restart Outlook and check if the highlight tool is back.

If that doesn’t work, you can create a new profile. Go to Control Panel > Mail > Show Profiles > Add. Set up your email account again. This is a bit of a hassle but often fixes deep issues.

How To Highlight In Outlook Desktop

Now that you know why the tool might be missing, let’s make sure you know how to use it properly. On the desktop version (Outlook 2016, 2019, or Microsoft 365), the highlight feature is in the Format Text tab. Here’s a step-by-step:

Open the email in a new window (double-click it).
Select the text you want to highlight.
Click the Format Text tab.
Find the Text Highlight Color button (it’s in the Font group, usually with a yellow highlighter icon).
Click it to apply the highlight. You can also click the dropdown arrow to choose a different color.

If you want to remove highlighting, select the highlighted text and click the same button again. It toggles on and off. I use this all the time for marking action items in emails.

Keyboard Shortcut For Highlighting

There’s no built-in keyboard shortcut for highlighting in Outlook, but you can create one. Here’s a workaround:

Add the Text Highlight Color button to your Quick Access Toolbar (the small toolbar at the top).
Right-click the button and choose Add to Quick Access Toolbar.
Now you can press Alt followed by the number key that appears (e.g., Alt+4) to activate it.

This isn’t a perfect shortcut, but it speeds things up. I’ve set mine to Alt+1 for quick access.

How To Highlight In Outlook Web

The web version (Outlook.com or Office 365) is a bit different. The highlight tool is there, but it’s not always obvious. Here’s how to find it:

Open the email by clicking it (it opens in the Reading Pane by default, but you can also open it in a new tab by clicking the pop-out icon).
Select the text you want to highlight.
Look at the toolbar above the message. You should see a Highlight button (a yellow highlighter icon). If not, click the three dots (More actions) and look under Format.
Click the button to apply the highlight.

One thing to note: the web version sometimes only shows the highlight button after you’ve selected text. So always select first, then look. Also, the color options are limited—usually just yellow.

How To Highlight In Outlook Mobile

Unfortunately, the Outlook mobile app (iOS and Android) does not have a highlight feature. This is a known limitation. If you need to highlight text in an email on your phone, you have two options:

Use the web version: Open Outlook.com in your mobile browser and use the highlight tool there.
Copy to another app: Copy the text to a note-taking app like OneNote or Google Keep, highlight it there, and then paste it back (though formatting may not carry over).

I’ve tried both, and the web version works best. Just request the desktop site in your browser for a better experience.

Alternative Ways To Highlight In Outlook

If the built-in highlight tool still isn’t working, you can use these workarounds:

Use Word: Copy the email text into Microsoft Word, highlight it there, then copy it back into Outlook. This preserves the highlight.
Use a color font: Change the text color to yellow or a bright color as a substitute. It’s not the same, but it draws attention.
Use categories: Assign a color category to the email itself (e.g., “Follow Up” in red) to mark it as important.
Use a third-party add-in: Some add-ins like “Highlight It” add extra highlighting options, but be cautious with security.

I prefer the Word method because it’s reliable and doesn’t require extra software. Just make sure you paste as plain text to avoid formatting issues.

Common Mistakes When Highlighting In Outlook

Even after fixing the issue, people often make these mistakes. Avoid them to save time:

Not selecting text first: The highlight button applies to selected text. If you click it without selecting, nothing happens.
Using the wrong tab: The highlight button is in the Format Text tab, not Message or Insert.
Forgetting to open the email: As mentioned, the Reading Pane doesn’t support it.
Assuming all versions are the same: The web and mobile versions have different interfaces.

I’ve made all these mistakes myself, so don’t feel bad. Just double-check each step.

Frequently Asked Questions

1. Why can’t I highlight in Outlook on my Mac?
Outlook for Mac has a different interface. The highlight tool is in the Format menu, but it only works in HTML emails. If it’s missing, update your Outlook for Mac to the latest version. Also, ensure you’re not in the Reading Pane—open the email fully.

2. Why is the highlight button grayed out in Outlook?
A grayed-out button usually means the email is in Plain Text format. Switch to HTML or Rich Text in the Format Text tab. If you’re composing a new email, change the format before typing. For received emails, you can’t change the format, so copy the text to a new message.

3. Can I highlight text in Outlook without opening the email?
No, you cannot highlight in the Reading Pane. You must open the email in a separate window. This is a deliberate design by Microsoft to keep the preview area lightweight. Some third-party tools claim to add this feature, but they’re not reliable.

4. How do I highlight in Outlook 2010?
Outlook 2010 has the highlight feature, but it’s in the Format Text tab, same as newer versions. However, if you’re using the web version or an older build, it might be missing. Update to the latest service pack for Outlook 2010 to ensure full functionality.

5. Why can’t I highlight in Outlook after an update?
Updates sometimes reset settings or change the ribbon layout. Check if the highlight button was moved to a different tab or group. You can customize the ribbon by right-clicking and selecting Customize the Ribbon to add it back. Also, disable any new add-ins that came with the update.

I hope this article has answered your question “why cant i highlight in outlook” and given you practical solutions. The fix is usually simple—open the email in a new window or switch to HTML format. If you’re still stuck, try the profile repair or add-in disable. Remember, the highlight tool is a great way to organize your inbox, so don’t give up on it. Happy emailing!