Microsoft has been rolling out the new Outlook for Windows, but many users prefer Outlook Classic for its stability, offline support, and enterprise features. If your emails are opening in the new Outlook by default, here’s how you can make sure they always open in Outlook Classic instead
Set Classic Outlook as the Default Mail Client
Step 1. Open Windows Settings.
On the Windows search bar, type Settings, then click Settings from the search results.
Step 2. Go to Apps > Default Apps.
Step 3. Scroll down to Outlook (Classic).
Step 4. Click every extensions.
Step 5. Select Outlook (Classic) icon and Click Set default
To test, open an .eml or .msg email from NetDocuments. Outlook (Classic) should open instead of the New Outlook.