Email Button Opens Internet Explorer Instead of Outlook? Here's the Fix

Why Does This Happen?

When you click an email button on a website, it uses something called a mailto: link — a special web protocol that tells your computer to open an email app. The problem is that Windows doesn't always know which email app to use.

If Internet Explorer (or a blank browser tab) opens instead of Outlook, it means Windows has not been told that Outlook Classic is your default email handler. Windows falls back to the browser, which cannot handle email — resulting in a blank or broken page.

The Fix: Set Outlook Classic as Your Default Email App

Step-by-step guide (Windows 11)

1. 1
   Open Windows Settings

   Press Windows + I on your keyboard. Settings will open instantly.

2. 2
   Click "Apps" in the left sidebar

   Then select Default Apps from the submenu.

3. 3
   Search for "Outlook" in the search box

   Type Outlook and you will see results appear — look for Microsoft Outlook (Classic), not the new Outlook.

4. 4
   Click on Outlook Classic

   This opens a list of file types and protocols that Outlook can handle.

5. 5
   Find "MAILTO" in the list and click it

   A pop-up will appear asking which app to use. Select Outlook (Classic) and click OK.

6. 6
   Test it — click any email button on a website

   Outlook Classic should now open directly with the email address already filled in. No more Internet Explorer!

One-Click Fix: Download the .bat Script

If you need to apply this fix on multiple computers — or just want it done in one double-click — download and run this script as Administrator.

Right-click the downloaded file → Run as Administrator. It completes in under 5 seconds.

Why Outlook Classic and Not New Outlook?

Windows 11 ships with the new Outlook app which is a web-based version of Outlook. Many users and businesses still prefer Outlook Classic because it works offline, integrates deeply with Exchange/corporate email, and retains the familiar interface.

If you have both installed, Windows may default to the new one — which is why your mailto links might be going to the wrong place even after a previous attempt to fix it.

Comparison: What Each Option Does

Still Not Working? Try These

Outlook Classic doesn't appear in the list

Open Outlook Classic at least once before changing the default. Windows only registers it as an option after it has been launched for the first time.

The fix works but reverts after Windows Update

Windows updates can reset default app settings. Re-apply the fix from Settings → Apps → Default Apps, or run the .bat script again.

You're on Windows 10

Go to Control Panel → Default Programs → Set Default Programs, select Microsoft Outlook, and click Set this program as default.