If MailTo links are not opening or working in Microsoft Outlook, you need to set Outlook as the default app for MailTo links.

Microsoft will force install the new Outlook email client on Windows 10 systems starting with next month's security update.

Microsoft has started force-installing the new Outlook email client on Windows 10 systems for users who deploy this month's KB5050081 non-security preview update.

If you cannot configure email or set up a profile in Outlook (classic), use the Outlook Profile Setup Troubleshooter to fix the issue.